I am based at Redhill and frequently run up to Manchester, Hull and the Western Highlands or Aberdeen. In a helicopter I have the advantage of using the Helilanes but when unavailable it is no trouble to skirt East of the London zones.
For Manchester or Wales I find it easier to skirt West of Heathrow. I have taken a crossing service but didn't find it saved enough time to be worth the effort. A Far borough crossing service is more useful.
Gatwick crossing is also quite good, though not if I am launching from Readhill as the time spent holding means i could just go around. Recovering back to Redhill from South it's much better as you can call ahead in sufficient to me.
In short - go for it.