Wohoo!  Meeps second urinalysis was clear - no crystals, no blood!  So,
currently no cystitis!

That's the good news.  The not-quite-so-good news is that her urine is
rather concentrated, which generally means she's not drinking enough
(which is at least one thing that predisposes her to another attack)

So now, I'm looking for suggestions on how to add more H20 to her diet.
 This is what I've tried, or am doing now:

She won't eat her dry if it's even slightly damp.  But she will eat the
prescription dry, so we'll keep her on that for now.

She's very finicky about her wet food, having trouble finding a brand
that's low ash/magnesium that she likes - won't touch the prescription
wet.  Suggestions on canned/moist US or UK catfood that's low
ash/magnesium, that I can try?  Senior or Light types preferred, but
we've already tried Science Diet senior, no go.

She has a gravity-fed waterer, which has helped some.  Finding a place
for something that requires power is - problematical.  Also, since we're
Americans in the UK, and going home relatively soon, I'm a bit reluctant
to fork out the large number of £'s for a UK version, just to sell it in
6 months' time.

Vet has suggested:
- Try setting out different types of water containers. I'd like to know
if anyone has any idea which type of container cats prefer - plastic,
ceramic, metal, whatever?
- Give her access to the bathroom, so she can lick wet tub if she
desires (we do; she doesn't. Not going to allow her access to toilet
water - she licks me too.)
- Try making catfood flavored icecubes (pour warm water over dry
catfood, drain, freeze), drop one in her water.  Vet just heard of this
one, wants to know if it works for me.  I'll try this modified, and am
just offering her an additional bowl of catfood flavored water.  Usually
we give her the water from a tuna can.  Maybe I'll freeze that instead
next time, and drop a cube of that into her water.

Any other suggestions?

jmc