I'm no expert but this little baby from contour looks good.
High definition and has two lasers that 'spot' where the shot is to allow you to position the camera correctly on your lid and the lense rotates to ensure you get the shot straight too (not leaning over to one side or the other).
Lots of head-cams reviewed in MBUK this month (including this one).
Looks like you already have the rest of the requirements for a good video i.e. quality riding, decent rider and amazing scenery and lighting. All you need is the above camera or something like it.
I take it you are Mr Basque mtb so if you are a VAT registered you get it VAT free (if you are even in the UK) and can probably write it down as a business expense so go for it.