I didn't like my ladder-based ramp. It was heavy, clumsy...and got me teased relentlessly at Sywell ;)
So I decided to either make, have made or buy something more compact . . . and found this on ebay: a portable wheelchair ramp, capable of carrying 28 stone...and designed to be carried by taxis, etc. I have played with it, but as my van is currently at the garage, I haven't had the chance to actually try the ramp out properly.
It is a nice little design made from aluminium extrusion, which telescopes in three stages from 28" to 5' (which is a bit shorter than my own ramp, but which I think will be fine) and has a grippy, sandpaper-like running surface. It comes in its own, conveniently designed zip-up canvas bag, compact enough to put in the seat-well too; better than having to go to the trouble of securing a ramp to the roof-rack and having to check the straps at every service station.
£44 including postage.