We are renovating our house and currently the kitchen is being tiled. The tiles are 60x30 and the original tiler indicated these will need to be laid in thirds (rather than half offset) as the tiles can be slightly bowed, and this will minimise the effect - it actually shows this on the tile's packaging as well. Unfortunately, due to other delays they are using someone else to lay the tiles and despite my request, have laid it half offset. Essentially my question is, if left as it is, will this be problematic in the future? The build is already massively delayed and the tiles used were from a limited stock, so may not be replaceable - I have been in contact with the tradesmen we are using and have advised them of the situation and fully expect them to rectify the issue at no extra cost - but, if it the issue is mostly aesthetic, I would consider it acceptable for money to be taken off the final payment and they continue to complete the work (currently about 50% of tiles laid but not grouted yet).