Honor Blackman

That got your attention didn't it?
Midsomer Murders Srs 6 Ep 1 on Tue 7 Mar 2023 shows a sequence about 20 min in of her driving an XK Jaguar along an overgrown runway.
Any idea where?  There was a smallish windsock at a runway intersection but no other obvious features. 

No.  There was clearly a tarmac runway which had become overgrown and in any case it was one of the earlier episodes (Srs 6 Ep 1) with John Nettles not Neil Dudgeon.
I thought it could be Oakley because the filming did use locations in Buckinghamshire in the early days; my sister appeared as an extra in 2 episodes.

I've answered my own question.
Ran through the episode a bit slower and found that the runway surface was actualy concrete when I thought it had been tarmac.
The main runway intersects at pretty much a right angle.
There is a B1 hangar visible in the distance.
So my conclusion is that the airfield is Oakley!!

I would say that Oakley (Worminghall) airfield is the one you mention as it's only a few miles from Thame, Oxon. A Lot of filming is done in Thame, and close by Long Crendon, especially the High Street. Within the Eight Bells Pub there is / was a signed photograph of John Nettles on a wall.
Organised Tours of the locations used in Thame can often be seen taking place.

Nearby Chalgrove was used during the filming of an episode of 'The Prisoner' back in about '67.  They had to play with camera angles so you couldn't see the rear cockpit of the Meteor; Finmere (also nearby) was used in the opening episode ot 'Pie in the Sky'.

Plenty of my photographs of oakley (Wornal) airfield, including the Windsock from years ago, and a bit more recently.!