velodocuk wrote:
I've got two removable tiled sections in my new shower room - one for
access to underneath the front of the shower tray and one caps the
boxed in soil pipe (air admittance valve type).

I'd like to seal the joins but preferably with a sealer which would be
relatively easy to remove if I need to remove the sections.

Silicone bathroom sealer can be difficult to remove tidily. Can anyone
suggest an alternative for this particular use - decorator's caulk?

No, it doesn't look good unless painted. Silicone is usually easy enough
to cut off with a sharp knife and if it's going to be re-sealed after
access it'll look neat enough.