Hi Stik
Thanks for starting this thread.
I had my first solo last week at Denham and our local training area is the same as where you got a bit lost. It's certainly not the easiest bit of the UK to fly around as I have found whilst practising nav with my instructor. I think I'll be going out there alone at some point soon and your post has reminded me to keep a close eye on the map/wind/disused airfields etc. I'm also going to ask my instructor to take me through a training D&D fix with the nice people on 121.5 next week just in case I have similar problems to you in the future (I know one of my "land aways" for the QXC will possibly be Cranfield so it can only help!).
I do hope you feel better about the experience now especially following the positive responses from ATC on this thread. It has certainly made me feel more able to call them in future if I become unsure of my position.
Cheers
Andy