There are only 70 or so gyros operating inthe UK (ie they have a current permit to fly). Most are single seaters powered by 2-stroke Rotax engines (so the McCulloch thing is a red herring).
There are lots of reasons why they aren't more popular in the UK, for example:
You can't (as of today) purchase a factory built machine. You either have to build one yourself (eek!) or buy one used which someone else has built (double eek!)
They have a poor safety record. None of the aircraft flying up to now in the UK have been approved to any engineering standard, they are all old designs with approvals based on "service experience". As a result many have some undesirable handling characteristics which make them vulnerable to mishandling. The poor accident record has made our regulators nervous about approving new designs or changes to old ones, which makes it very expensive and time consuming. This discourages people form innovating or building modern, safe machines - so the existing problems are perpetuated.
Because demand is low (due partly to the lack of aircraft) most people have to travel a long way to get to an instructor - much further than to learn on microlights or fixed wing, so the bar is raised once again.
Gyro cost more than microlights - used single-seat gyros have typically be selling in the £7k to £10k range. For that money you could get a decent 2-seat flex wing.
The good nbews is that it's all starting to change. The Magni M16 (see earlier in the thread) is finally approaching approval, and the MT-03 (
www.rotorsport.org) has completed all its testing and is in the final throes of the approval process (mine is due any day now!). With safe factory built machines available gyros are likely to become much more popular, though they will always remain a niche. That said, the MT-03 was the second largest selling microlight in Germany last year, and seems to be very popular with pilots looking for something different.
So why do we fly them? Because they are huge, huge fun. They are manouverable, have a wide speed range, draw a crowd wherever you go and make a fantastic "woc-woc" noise as you pull "g" - what more could you want?
For more info take a look at the British Rotorcraft Association website
www.gyroplanes.org