I'm currently doing the evening class Dayskipper course which started in September and finishes at the end of March and cost £125. I think £245 is probably the going rate for the intensive course, but my concern would be assimilating so much information in just four days. Admittedly I started the course with hardly any previous knowledge but even for an experienced boater I reckon you'd be pretty hard pressed to cope within such a tight time frame. And that's even before you start the homework!
Having said that, although I think it's an excellent course I must admit it is now starting to drag a bit after so many weeks and I'm looking forward to finishing it. For someone with your obsession with speed, Suzuki, that may well be an important consideration
One other point you need to check is whether the course includes the new GPS/electronics section, because the RYA has postponed its introduction. Probably worth waiting for a course that incorporates it.