Good news -
I found some tiles for sale which were a close enough match (a nice old-fashioned green) to the old ones in our kitchen that they'd do for the wall behind the new sink.
Bad news - not local so I had to get em delivered, which put the price of a couple of boxes up significantly.
More bad news - when the bloke doing the work opened the boxes this morning, the majority were broken.
Good - when I phoned the sellers their customer service person Rebecca was helpful & efficient. She said if I sent photos before 4 pm I could have new ones delivered on Monday - and that's now booked, the photos of the broken tiles being satisfactory. She's requested that the delivery be done using their own transport rather than the 3rd party courier used before.
More good - Matt the kitchen & bathroom man (who's already done a good job on the bathroom, to Mrs B's delight) is happy to come back to finish the job. He'll finish early today, when he's done everything else, & we'll fix the date for the tiling when the new tiles have been safely delivered.