I'll be grateful for some advice on re-tiling a bathroom prior to
fitting a new bathroom suite.

Current, the wall at the back and foot of the bath is tiled right up to
the ceiling; that at the head of the bath and behind the WC and hand
basin to a height of 1.2m, as is the "return" on the side of the hand
basin. Most of the existing tiles are sound but there's a large area
behind the bath, roughly corresponding to the area where the spray from
the power shower hits, where they appear to be blown - they have a
hollow ring when tapped. My intention is to put the new bathroom
fittings in the same position as the existing ones and to tile roughly
the same area of each wall.

I propose to lever off all the lose/blown tiles. If the underlying
plaster is sound the plan is to re-fix them using a waterproof tile
adhesive. If it is not, then I'll hack off the old plaster and skim up
to the level of the existing tiles. But I want to try to avoid
re-plastering the whole wall if possible.

Questions a
1. Does the above plan of action above seem about right?
2. If re-plastering part of the wall behind the bath is found to be
necessary what is the best medium to use?
3. Where the existing tiles are sound, what is the best way to
prepare them as a base for the new ones?
4. Is it necessary or desirable to use a special adhesive and/or
grout in the area that will take the spray from the power
shower, other than the normal waterproof stuff. If so, what?
4. What is the best way of dealing with the "double thickness" of
tiles the I will end up with on the exposed edges of the splash
back (e.g. behind the loo and basin) given that the standard
edging strip is designed for a single tile thickness. Do I use
this and pack the gap behind with grout?

When it comes to fitting the new bath, what are people's thoughts on
whether it is better to fit the bath first and tile around it, or tile
first and fit the bath to the tiles?

Many thanks for your help.

Ververka

Cheltenham, Glos