That's precisely what went through my mind Grahamm - when I looked at in daylight (it were dark when it got banged), the usual surface dirt / marks laid by the hugger position seemed out to the RHS by 3-4mm (not much, but enough to be a concern), coupled with an obvious rear-end twist (looking at the back of the bike, lowish down, the pillion pegs were obviously out of sync) - again, in the dark, I put it down to possible subframe damage initially until I saw the swingarm in daylight.
It's currently in my usual bike shop (and they're pretty good, what they don't know about bikes isn't worth knowing), they reckoned it maybe looks worse than it actually is.
