Redecorating after insurance claim?

Just before xmas i had a burst pipe due to the bad weather. it wasnt huge, but 1 wall of the bathroom, landing ceiling, kitchen ceiling and floor and various plaster bpard replacements. The builders are in at the moment. the only part of the wall damaged is the wall my shower sits on. it is tiled (30x20) floor to ceiling and they have said that these particular tiles arent made anymore and want to try and match the tiles with perpex type stuff. now, my whole bathroom is in these tiles so if they do their plan then my bathroom will not be the same. it cost alot of money to get done in the 1st place. i have rang my insurence and said i am not happy about there plan but said they only replaced "the damaged bit". So this is like buying a 3 piece suite and the armchair breaks and them replacing it with a different armchair. am i within my rights to push for them to redecorate all the bathroom with the same tiles? as they have said if they do this i will have to pay the difference