Thanks everyone.
Think I'll give the ECE thing a go then. There's a 300 in October that runs from 0900-0500. If I am full value, I'd have a good 2.5 hours or so to wait for a train home, and if I do it in the same time I did my last 300, I'd have about 5.5 hours to wait. So rather than waiting in the cold at a station, I figure I may as well cycle 100km in the direction of home (There's a station 101.7km away!), this gives me a 400km ECE. If I'm not gambling the 300, there's very little to be lost in trying to ECE.
I take it no issues with the calendar being BRM? Am I right in thinking ECE's are done at BR pace? Meaning I'd have... *rolls dice* 27 hours 12 minutes total?
Cheers
J