My last two audaxes have included ece. I fill in the online form, with just a mention of places I'll be going through, then email it, send the payment, and email Martin the gps route I'll be taking.
Chalfont is about 70k by bike, so I'm thinking of looping it to 100 (did that to Cirencester HoE 300), to make 600 overall (my first). I hate driving to places on my own, begrudge paying for diesel, and as a committed cyclist, feel I should cycle to starts (apart from the Dean).