In reply to andy: Rothwell is now sadly no more, or at least was cancelled this year due to a lack of support and increasing costs. Dewsbury is still on and fast, though had to be rescheduled due to snow this year.
It's a few years since I did the Abbey Dash, and starting just behind the 40min marker didn't find it too bad beyond the little contraction just before the Yorkshire Post building. The road is very wide, especially with the new bus lane now put in. I don't recall arriving that early (I ran down as it starts a perfect warm up distance from home).