Hi William - I too run in Ascic road shoes and first pair of trail shoes I bought were trail equivalent...never again. Fell apart and quickly lost any cushioning (maybe my extra timber
), and at that time I didn't do severe fell or mudbath xc.
Many rave reviews of Mizuno Wave Harriers and I've owned (and abused) Inov8 Roclites; they're ace. Both bit pricey but will not go wrong.
If you want a cheaper start and might be doing more mud that track then I'd look no further than More Miles Cheviots... range of colours, Inov8 tread rip off and well cushioned - won't last as long despite name. 30 quid plus P&P though so happy days.
NtS