teryc, Did your instructor fit the K21's adjustable back rest for you? Ours have these, which are additional fibreglass seat backs with a couple of light alloy arms that go back to engage in the seat mounting structure. Each seat back offers you a choice of two positions to sit further forward than the normal one. There are two different additional seat backs depending on whether you are sitting in the front or the back.
If you can reach M3 Junction 5 at a weekend, you would be welcome to come and try our K21 for size.