I doubt they will let electrics race in the national series yet, there just aren't enough of them around in the UK for it to be viable. A separate 1/8 electric race (even a one-off, like the US 1/8 electric nationals this year) would be great, but suffers from the exact same problem as before stated.
There aren't many rules that can be imposed on electrics, though I am writing a set of rules for my local club (was appointed 'guru for all things electric' yesterday at the club AGM
) which I'll post up here as a suggested set to use around the country. I'll probably base a fair amount of it around the ROAR rules, though will tweek it slightly.