That most likely cannot be safely repaired. Usually parts of the case interlock to keep out water.

In theory, if the manufacturer would supply a replacement housing, a competent person could transplant the parts but I doubt anyone would ever do that. That's not an expensive unit to replace.

Some Mira showers did have an easily replaceable lower enclosure part, I'm not sure if that is one of those. You could phone Mira for advice but really its a no-brainer for the landlord to hire an electrician to replace this.

I would not consider the opening in the wall to be safe either. Water will get in, certainly steam and condensation may cause problems in that wall.

You don't plan to do the work yourself, but this isn't notifiable under part P.

Part P section 2.5 says its not notifiable if you are not

a) adding a new circuit, 
b) working in a Consumer Unit 
c) adding or altering an existing circuit in a special location. 

Replacing a broken appliance with an identical new working unit isn't adding or altering the circuit.

Which says

If you’re replacing an existing electric shower unit like-for-like, you may be able to install it yourself. In this case, the power and water cabling is already in place, and installing a new one simply involves fitting a new shower unit and riser rail. However, if the new shower unit has a higher wattage than the old one an electrician should replace the unit as the cabling may need changing. If in doubt, always err on the side of calling in a professional.

Find Any Answer says

"The fitting and replacement of cookers and electric showers is not notifiable unless a new circuit is needed."

Repair

That most likely cannot be safely repaired. Usually parts of the case interlock to keep out water.

In theory, if the manufacturer would supply a replacement housing, a competent person could transplant the parts but I doubt anyone would ever do that. That's not an expensive unit to replace.

Some Mira showers did have an easily replaceable lower enclosure part, I'm not sure if that is one of those. You could phone Mira for advice but really its a no-brainer for the landlord to hire an electrician to replace this.

I would not consider the opening in the wall to be safe either. Water will get in, certainly steam and condensation may cause problems in that wall. Most importantly, a child or other person might get a wet hand through that gap and touch a damaged or wet electrical cable.

Part P

You don't plan to do the work yourself, but this isn't notifiable under part P.

Part P section 2.5 says its not notifiable if you are not

a) adding a new circuit, 
b) working in a Consumer Unit 
c) adding or altering an existing circuit in a special location. 

Replacing a broken appliance with an identical new working unit isn't adding or altering the circuit.

Which says

If you’re replacing an existing electric shower unit like-for-like, you may be able to install it yourself. In this case, the power and water cabling is already in place, and installing a new one simply involves fitting a new shower unit and riser rail. However, if the new shower unit has a higher wattage than the old one an electrician should replace the unit as the cabling may need changing. If in doubt, always err on the side of calling in a professional.

Find Any Answer says

"The fitting and replacement of cookers and electric showers is not notifiable unless a new circuit is needed."

Part P section 2.5 says its not notifiable if you are not

a) adding a new circuit, 
b) working in a Consumer Unit 
c) adding or altering an existing circuit in a special location. 

Replacing a broken appliance with an identical new working unit isn't adding or altering the circuit.

Which says

If you’re replacing an existing electric shower unit like-for-like, you may be able to install it yourself. In this case, the power and water cabling is already in place, and installing a new one simply involves fitting a new shower unit and riser rail. However, if the new shower unit has a higher wattage than the old one an electrician should replace the unit as the cabling may need changing. If in doubt, always err on the side of calling in a professional.

Find Any Answer says

"The fitting and replacement of cookers and electric showers is not notifiable unless a new circuit is needed."

That most likely cannot be safely repaired. Usually parts of the case interlock to keep out water.

In theory, if the manufacturer would supply a replacement housing, a competent person could transplant the parts but I doubt anyone would ever do that. That's not an expensive unit to replace.

Some Mira showers did have an easily replaceable lower enclosure part, I'm not sure if that is one of those. You could phone Mira for advice but really its a no-brainer for the landlord to hire an electrician to replace this.

I would not consider the opening in the wall to be safe either. Water will get in, certainly steam and condensation may cause problems in that wall.

You don't plan to do the work yourself, but this isn't notifiable under part P.

Part P section 2.5 says its not notifiable if you are not

a) adding a new circuit, 
b) working in a Consumer Unit 
c) adding or altering an existing circuit in a special location. 

Replacing a broken appliance with an identical new working unit isn't adding or altering the circuit.

Which says

If you’re replacing an existing electric shower unit like-for-like, you may be able to install it yourself. In this case, the power and water cabling is already in place, and installing a new one simply involves fitting a new shower unit and riser rail. However, if the new shower unit has a higher wattage than the old one an electrician should replace the unit as the cabling may need changing. If in doubt, always err on the side of calling in a professional.

Find Any Answer says

"The fitting and replacement of cookers and electric showers is not notifiable unless a new circuit is needed."