Kirsty, as I said don't worry about it unduly, Vintage Atco made a valid point about getting in touch with the unit, but it's far more likely that they would have contacted you by now if they wanted to take it further - after all they knew who you were and where you were flying to.
Severn's comments were totally irrelevant and very unhelpful, I dont know if he/she was trying to wind you up, but ignore them.
The only people who fine you for flying infringements are the UK Courts, and this is only after the CAA have investigated the matter thoroughly and decided that there is a good case to prosecute the individual because they've not just transgressed, but there's more to the case that needs investigation than may initially meet the eye.