Cannot fault the Makita range, stay with the same battery system if possible.
Have 30 + Makita tools and batteries, recently purchased the 100mm pruner, again excellent.
Are you tiling past the shower door or flush with shower door frame?
You could keep the tile backer board and tiles inside of the door frame which is then fixed back to plasterboard depending on the width of door.
Would need a very good seal.
You want a T shape trim to cover both the board and tile or a straight edge trim to cover just the backer board.
Have a look at:
https://www.protilertools.co.uk/categories/tile-trim
https://pureadhesion.co.uk/trims/
Personally I would not tile onto a skimmed plasterboard wall, they will become loose.
I would fit 6mm Hardie backer board on all 3 sides and space accordingly with packers for even dimensions.
These have a PVC or EPDM inner tube usually.
Is the hose failing or the fitting?
Is the supply in copper or plastic?
Look as though they have been inside the cistern.
I did try cooling the slab with the ASHP but the family discipline closing windows and doors during the hot periods was iffy so gave up.
On sunny days the UVC is 67c with the immersion / PV diverter by 10am.
The lower ground floor bedrooms are north and east facing with smaller windows so not an issue.
The first floor bedrooms with vaulted ceilings are the warmest and AC is just so effective and the running cost offset by PV (+FIT).