OK, be gentle with me cause I'm getting quite emotional about this - that's the reason I'm looking for an outside point of view...
I recently took one of my rabbits, Poppy, to the vets for her annual jabs. While there, the Vet gave her the usual once over and announced that she had spurs on her teeth and would probably require a dental operation soon. At the time, we were two days away from going on holiday so the vet said that as she was otherwise looking very good for her age (she's 5) and about to go into kennels at a Rabbit Rescue place for 2 weeks, it would be better to wait till we got home to do the operation in order not to stress her out too much.
Taking the vets advice, I booked the dental for after the holiday. Lady at the kennels was advised of the vets advice and I signed forms allowing her to take her to her own vets should the teeth seem to be causing a problem while we were away. There were no problems while we were away.
A few days after we got back, Poppy developed the runs and I made her appointment immediately to be seen the next day. The vet found 2 maggots and diagnosed fly strike. I'm devastated. In over 10 years of owning rabbits, I've never had a rabbit with fly strike and never thought I would. 
I've been told that it's not my fault, that the teeth caused the runs and the runs attracted the flies and actually, I did well to get Poppy to the vets so quickly - it doesn't help, I still feel awful. I've also been advised that maybe the kindest thing for Poppy now - even though the fly strike is gone and healing - is to be put down
I've had a rabbit with occluded teeth before and I spent years (and many hundreds of pounds) caring for him. He had dental operations regularly - even though twice he stopped breathing while under. We kept him going for as long as possible and I'm not sure in the end that it was the kindest thing to do.
But that was before we had children when I had more time and spare cash to lavish on my bunnies. I'm worried that if I try the same with Poppy, we risk getting into the same hopeless rounds of worry again but that it will feel even worse while also worrying about money (which is tighter now I'm a SAHM) and having to drag my 3 year old and 8 month old backwards and forward with me to the vets for what could be very emotional visits. It seems Poppy's situation is worse than my previous rabbit too as he never got such bad runs or fly strike.
I feel like it's very soon to be 'giving up on her' but I'm also petrified of going through it all again with the added stress of doing it with 2 small children watching.
Would I be wrong to take the advice given and to put her down?