In reply to timjamesmedley:
I think it's worth pointing out that there are multiple goals here and perhaps they're getting confused.
For instance:
1. Getting stronger
2. Becoming a better climber
3. Getting up that boulder problem you're trying on the next go, or by the end of the session.
4. Have fun climbing, socialise with friends at the wall.
1 and 2 are very different from 3 and 4 in that they're both future goals. Completing some specific boulder problems this session might feel very rewarding and give you confidence but these are mental benefits not physical ones. It doesn't follow this is the optimum regime for no. 1, getting stronger.
For no. 1, simply getting stronger, the best route might be to stop climbing altogether and instead follow a modified calisthenics or weighttraining routine with additional fingerboarding/campusing. However this wouldn't help with 2, 3 or 4 at all.
But assuming you want get stronger by climbing it's important to distinguish between a peak performance (such as when you're trying to complete a limit boulder problem) and training. In the former you're trying to conserve as much energy and strength as possible and will want long rests to maximize your chances. In the latter, training, you're almost doing the opposite, trying to fatigue and breakdown muscle tissue as efficiently as possible.
If training is your intention then having longer rests is likely to be counter productive to seeing a strength gain at sometime in the future.