Just to clarify. The goods purchased are separate to any quote or estimate for labour and fitting?
If that's the case then id pay you're more than entitled to the goods and sack the fitters due to incorrect installation and say you've lost faith in their ability to install your bathroom correctly.
Looking at the pictures you've shown (and lets face it that's only a fraction of the whole works) i wouldn't feel that you would be left with a room that's fit for purpose.
Yes, don't want them finishing the job, just worried they won't give my goods let alone a refund for the tiles. I haven't paid any labour charges yet, and I am concerned they will demand some payment?