I think you really need to think about what you are reporting them for at that time. I would be surprised if the RSPCA would act on them being in a small hutch, no access to a run or thumping his back legs.
If at a given time they had no hay, food, water and were filthy they would be more liable to act and it is worth calling them. You need to have a factual complaint that they can see when they turn up.