I canonly answer this from a erspective of having been an Examiner for RoSPA for the past 35 + years having also done 10 years as an IAM examiner and as one of the three that wrote and delivered the RoSPA diploma for advanced instructors and having instructed more students than I can shake a stick at if that provides any type of credibility?
These days, all organisations have to be strict about speed limits, particularly on test for obvious reason.
That said, the training is not about speed, it is about building in sufficient margins of safety and getting you accurate in respect of postioning, forward planning and observation, risk assessment, observation links and the whole package.
You are not going to learn that at 100 MPH +
However, when you start, a good instructor will slow you down and what you will find is that as you become more comfortable with the techniques (bear in mind 99% of what you learn for the L test is crap and goes out of the window) your speed will increase naturally but with more time and a bigger bubble of safety built in.
I had a GSXR1100WP for a few years and compared to the R1, Blade and the like it was a dinosaur.
I would do an assesment ride and then for the last 7 or 8 miles I would give a demo just to give the person I was assessing an opportunity to see how the new techniques worked in practice especially through the twisties.
About 2 or 3 miles up the road I would have to slow down or stop for them to catch up and they would 9 times out of 10 complain that I was doing illegal or silly speeds as they were unable to keep up.
When I assured them that I had complied with or been under the speed limit the whole time, they were gobsmacked, but the penny dropped.
Advanced riding is not about balls out speed, but it is a natural by product of riding to a different standard, and whilst it may seem to you that you are riding slower, you will actualy be covering the ground quicker because of the way you use the road.
You cannot be trained at 100+ (which is one of the issues I have with some of the Bikesafe schemes), you need to be trained at a speed that allows you to develop and let the speed develop naturally.
You will not be as fatigued either, you will place less wear and tear on the bile and you will be a lot smoother…
I always use my old Sgt as a good example
When we got called to a shout, Barry (my Sgt) was one of the smoothest riders on the planet, and we young whippersnappers also considered him one of the slower riders.
We would shoot off at warp 9 and Barry would go at his pace, but he was never more than about 30 seconds behind us on arriving at the scene.
As you get older, that is when you learn that speed is not just about MPH.
Anyway, I am digressing, so sorry about that, but speed for the test is cast in stone for obvious reasons, but your training will allow you to ride quicker.
Both the IAM and RoSPA train according to Roadcraft the Police riding manual and these days the standards are very similar.
But it is not about badge collecting, it is about the quality of the training you receive, and there are some very good groups out there of which I have seen many over the years.
Hope that helps?