Performance Considerations
If you apply the usual recommended factors for surface & condition/slope/density alt along with factors required for UK Public Transport ops (generally x1.25<TORA for take-off and x1.42<LDA for landing), it would preclude use of a lot of your regular GA airfields. My general approach has always been to assume MTOM and nil wind (partly conservative and partly to simplify things). As an example, with my approach I've regularly used an airfield with TORA of 520m where commercial ops would require in the worst case 740m (landing on wet grass in low pressure/high temps). I've never felt particularly risky in ignoring commercial ops factors though what do others apply and can it affect your insurance in any way?