I've had a few situations like this.. couple of times I've been crapping myself for weeks about it. No points yet, but I'm also still on a probational license, 6 points max, terrified of losing it...
I wouldn't let yourself panic about it... do you know what type of camera van it was? Digicam (little hole in back door or panel with a lens sticking out) or gatso-esque with the back doors open and the camera on a tripod? If it was the latter, you would have noticed it flashing if it had you.. the digicams are buggers though because you can't really tell.
As a general rule, a 30 limit camera will trigger at either 33 or 35 mph (limit + 10% or limit + 10% + 2mph) depending on the local police force. Also, your speedometer will almost certainly read a couple of mph over what you're actually doing, for example mine reads 30mph when I'm actually doing 27-28 (I checked on a GPS tracker).
If you thought you were in a 40 limit, is there any chance that you actually were and then it was changed to a 30 without you noticing the signs? Just a thought...
Anyway, the best thing to do is not to worry about it. If it caught you it caught you, worrying won't help, but chances are you'll be ok. I've only ever seen the local van catch one person and he must have been doing 45 through a 30.. never seen it flash for anyone else and people rarely do under 33 on the stretch of road that it's usually on...
I'll keep my fingers crossed for you
