Thanks for all the replies. Very much appreciated.
So Trading
Standards got back to me yesterday and it seems that they think I have a case to be answered. In their eyes the original agreement for price was to lay the tiles and grout the floor. Tiles and grout being supplied by the customer and primer,spacers and adhesive to be supplied by myself.
Because the grout was chosen and bought by themselves I am entitled to ask for extra money for my time and cost as this was the customers perogative to change the grout, regardless of whether it was the wrong or right colour.
They have given me a communicative protocol to go through up until the point of launching a small claims writ against them. So this is what I'm going to do.
I will keep posting up each stage of the process so that if anyone on here ever comes across the same problem (I hope they don't) they'll know the correct move to make to move forward with recouping unpaid wages back.
I have taken on board the grout issue and will certainly look into where I can find Grout3000 in central Scotland and give it a whirl.
Thanks again for all the advice, suggestions and opinions lads and lassies.
EdinTiler