The Gen number is A030203 and is only £9 odd from electrue and you get a new gasket with it!
The usual problem fitting these is the earth wire dropping off which needs the cooker pulled out to re fit. You can often see the tag hanging just behind the hole (which is a soft metal plate behind the oven back) if you enlarge this with a slotted screwdriver to enable the tag to be pulled through with a fine point long nose pliers it will save a lot of effort.