Update from the vet: Caroline called me on the way home today to say that the results of the tests on the two stones were in and they are struvite, not oxalate.
So from one perspective its good we know what to look for.
She needs to be on predominantly wet food going forward, we'll just have to do her teeth for scale and polish once very couple years.
Lexy will have her next x-ray in April when she does her annual MOT, so I'll take her in for that, and then as a precaution we'll do the same x-ray every 6 months for 2-3 years just to make sure that she's really clear. This way we can be sure no more stones are forming.
But for now, we're sticking to the Urinary food, which madam has finally decided is worth her time, with the odd chicken or duck dome she loves.
Overall, Lexy has done well after the surgery, she's much livelier than before the surgery and she's now going to be on a bit of reduced food so she can lose some of the pooch on her belly.