Hi Pete,
I've got all the parts for a full heatermeter right here, all you need is the ciruitboard which you can order in from OSHpark for about a tenner
http://store.oshpark.com/products/heatermeterI've even got two maverick probes (one pit, one meat), to be honest I've had them a bit and can't remember what I paid for them, but I'll give you the lot for £75 inc. postage if you want it?