Thank you to all those who posted replies and sorry I have not replied sooner, but I have just been on a 24 hour shift at work.
Friday night, bunny seemed a bit down and was reluctant to go in his litter tray (painful), so wasn't peeing. He is quite a clean bunny and will only pee in his litter tray with the megazorb down. He was pooing where he was sat. He wasn't eating as much, although he was still eating bits, especially if we gave him something a bit different (he likes a lot of variety). He gets loads and loads of hay as we make our own on our fields, and it's really good quality stuff. Like I said, vet said he's never seen a bunny as healthy.
Anyway, I got concerned about him holding the wee in and did not assume it was because he didn't want to pee where he lay. Litter tray had very few poos in (although what was there looked quite normal), so I immediately started thinking the worst, what with all the stress he's been under recently. I started feeling round he tummy to see if it was hard/bloated and it wasn't, but when I was having a feel, a load of wee came out (which vet said is normal, although as you can possibly imagine, the sight of gushing wee was quite frightening at first, coming from a woman who has had animals all her life, grew up on a farm and has seen some horrendous things!). Anyway, I brought his litter tray into his big part of his hutch as I felt he was struggling to get through into his hideaway where the tray usually is, and he started to use it a bit more. He was eating much more by the next morning and was more happy in himself (this was Saturday).
Nevertheless, I made an emergency appt for him at our vets practice, and my husband took him in (as I had work). He always shows us up at the vets because she put him on the floor and he hopped round the place, a little stiff but nowhere near as bad as at home and actually hopping freely. Then my husband put him back on the table next to his box and said Zebedee jumped CLEANLY on top of his big carry box! How to show your owners up as liars in one swift move!! She examined him and he's fine in terms of digestive health, but said the Metacam could be upsetting him a little (I'm thinking he's very recently also had a long course of Panacur and a big GA for the xrays), so to ease off for a few days and then reintroduce (to help prevent tolerance also), at which point the dose may have to be upped depending what the specialist vet says.
The vet told my husband that we should allow Zebedee to have a little exercise now (he has been restricted due to the injury), so we opened his bottom doors and he has been allowed to come in and out as he pleases. Husband said he spent a lot of yesterday in the garden, hopping around, alternating between gentle little hops to some more fast hopping. He's more sedate today, lying in the bottom of his house, but I am happier to have got him checked out.
Thanks for reading.