remote key fob

Just to keep this short,what's the best way to determine what frequency the system uses so as to match up a replacement fob.
Mine's a 1995 on an M plate or do you go from the vin?
According to what I've researched so far it should be a single button running on 418 mhz but i could be wrong lol.

:bump2:

a bit of advice wouldn't go a miss here peeps.

Isn't there any information on the receiver. I thought all radio equipment had to have it's frequency on a plate (or sticker). Or even a part number from the receiver might get you an answer.

all the info you need is on here Remote Key Fob Replacement