No worries mate, the wireless thing I used is called a ELM327, do a search on ebay and a few will come up, they're not very expensive.
I'm not sure what time I'll be going to Combe, I think we normally meet around 8am, and aim to be there for 9-9.30 ish. I'm not 100% sure what time our track session will be, I've heard around 11am, but I'll have to check