Jetblu,
I've always been very sceptical at following "unpublished approaches" I've read enough reports of crashes whilst people try to fly "unpublished approaches" in below VFR minima conditions.
h88 - it depends where you're going. I know Northolt provide this service, and it being free of charge (at least it was a year ago). In that neck of the woods you also have: Oxford, Brize, Benson, Farnborough who will also gladly help you. If you're in trouble and you find your airfield is under minima, I would consider diverting to Southend because I like the place, call me bias though but Biggin Hill is one of the few places left where if the airport is below VFR minima (which I think they say is less than 5km visibility and cloud at or below 1000ft above the runway), they don't actually charge you the ILS fee. [plus its super easy - talk to Thames Radar, they give you vectors then finish the approach with tower / approach]
GTE - I have thought about that for a while - cheaper to fly, maybe even a little more fun! But I quite like flying longer distances, and being able to fly IFR when required (which correct me if I am wrong but I don't think you can do in a microlight?).
Hope this helps!