Thank you so very much for your replies, ladies. You're all saying things that my dog walking friends have said over the weekend so you've confirmed the other advice I've had.
So to address a couple of points you made, he has digestive issues in the past and anything with shell fish/fish/oil/ condroitin etc gives him an exploding bum 😆 but he was on another supplement for joints from a pup.
He loves to swim and we're near the beach, river and lakes but my vet says hydrotherapy isn't right for him because his meniscus cartilage may also be torn and swimming isn't good for that. He had 10 weeks at the hydro place after his last cruciate surgery but his recovery so poor and his leg so unstable that he never got in the pool only in the hydro treadmill which tbh I don't think did anything.
He was insured up to when he was bitten by an adder and very nearly died about 3 years ago. It was a baby adder which pumped all it's venom into him. His insurance rocketed to £150 pm so we shopped around and new policies were even higher so we decided it wasn't worth it. We paid for the last one and would again but at over £5k now between what we and the vet think, he's just not a good candidate for the surgery. 2 years ago he was fine when he had surgery but it took 18 months for him to recover and the vet and hydro centre were concerned he didn't do at all well. He should have been weight bearing after 10 days and still wasn't after 6 months. So it wasn't good. 2 years and every joint is arthritic, including toes, he's just not right for surgery because as you pointed out above, the restricted excersise while he recovers from surgery will mean he'll loose muscle tone and he might struggle to even walk due to the pain.
Having chatted to friends with dogs who know my boy, they've said the same as you - he's loving life and it's too soon to say goodbye. I'm looking after a neighbours dog once a week while her husband has cancer treatment and the two of them play together and really have fun. My boy still brings us his toys to play with him every day and can't wait to go for walks. He's happy, bonkers, loving as they all always are.
I have read about people whose dogs have recovered without surgery for cruciate, too. My step sons spaniel did but only after 8 weeks crate rest and again that would mean he'd loose muscle tone.
Every night, he gets onto the bed with us and falls asleep in my husbands arms (used to be me years ago 🤣🤣) and so like all of you with pets, I dread that day. But it's not yet.
Anyway love and hugs to all of you have have lost or are facing 'that decision ' with a pet.
I'll let you know how we get on when we're back at the vets in 2 weeks.
Again, a huge thank you. It really helps to talk it over and hear other's experiences.
The price you pay when you love deeply and say goodbye is enormous.