Wibu to ask that dd doesn't get put on this pony for a while?

[Noitsnotteatimeyet]

At one of dd's riding lessons she often rides a particular pony who is known for being quite tricky

Dd is the most advanced rider in the group so when this particular pony is in the lesson dd almost always has her.

Dd loves riding her as she's very forward-going and apparently she's good to get in an outline but at the start of the lesson she often bucks a lot - think rodeo-style bucks ... dd's usually glued to the saddle but last week it was the first evening lesson in the outside school and the pony was wildly overexcited. She did a series of enormous bucks and dd came off. She got straight back on again and the pony was apparently well-behaved for the rest of the lesson but dd had jarred her back quite badly and ended up missing two days of school.

WIBU to ask the instructor not to put dd on this particular pony for a while or is it all just part and parcel of learning how to ride?

Ponies and horses are very good at masking their pain. It may well be that the pony bucks at the initial pain and then gets on with it as it knows it has no choice. The local rding school near me is very well thought of. However none of their horses are insured for vet bills and the owners rarely get a vet out until the very last moment. They simply aren't as proactive about diagnosing an unhappy or uncomfortable horse as a private owner would be.

I would definitely be asking the instructor / yard manager why the pony bucked and would be interested in their reply. A riding school horse shouldn't buck for the first however minutes every time it's ridden (nor should any other horse!). As others have said, horses can look great, but still be in pain from a pinching saddle.
(My mare used to buck out of excitement, but that wasn't continuous bucking - that would be one buck when you went into canter when out hacking!)

Biggles - you describe a 'yippee' buck!