>>>
>>>All now working smoothly (literally). I'm currently recalculating the average every time a new orientation event comes in. Processor seems to cope (g) and it makes for a very realistic damping effect.
>>>
>>>Had a few moments panic but it turned out the device compass needed recalibrating - was getting some *very* strange results beforehand tho.
>>>
>>
>>Sure it wasn't on your way from the pub to home ?
>
>No. Just tried it coming back from the pub. Worked perfectly. Just led me into the ditch a couple of times :-}

I see you used the definite article when mentioning "ditch". So I assume it never got you into any wrong ditch, but The Ditch. I conclude the solution is working as advertised.