Going to retile the bathroom and at present has tiles halfway up the wall around the bath which has a wall mounted electric shower and am going to tile to the ceiling,have started to take the old tiles off along with the plaster behind and wondered could i just take all the plaster off and tile direct to screed or should i replaster the the bad bit and retile?thinking along the line of if the new tiles have to come off in the future i don't want to be pulling the screed as well although it is sound as is the present plaster,will be using Bal apd primer and Bal blue star adhesive.