wow, thanks for all of the replys.
i can now understand that i should have used some flexible adhiesive aswell, but taking it up and starting again is not an option for me at this stage. the wall tiles are laid straight on top of the floor tiles, so im assuming some of these would come up aswell if i tried to remove the floor tiles.
I will remove the grout on the floor and use some flexible stuff, hopefull i will get away with that, if not, once i have more time and more importantly money, i will take up the floor and start again.
can someone reccomend me a good quality flexible grout? or provide a link??
BTW, it was not a professional tiler or builder who laid the tiles, it was a member of the family who did it for free.
I wish i had found this site a while ago so i could have bought some proper stuff!!
Thanks for the advice
Ian