After discovering (thanks to people on here) that in order to replace an air pipe on the front right I’d need to drop the strut, I’m wondering if it’s best policy to just replace the airbag whilst it’s out and also the front Left. Or is it best to replace the entire strut as well as the airbags? It’s a 2011 Autobiography with 65k miles which seems like it’s had an easy life, but I’m wondering what the consensus is on this. Is there any other maintenance I should do whilst doing this?

Check the condition of the rubber where it folds back on itself at the normal ride height. Any signs of cracking and I’d replace them. With that low a mileage the struts should not need replacing. Some say it’s difficult to just replace the air bags and get a good seal on the shaft but plenty of YouTube vids showing it being done. Depends also on your budget. When I had a leak ( cracked rubber) I replaced both complete struts each side just because it was quicker than replacing just the bags.by all accounts the rear bags are tougher and mine didn’t show any deterioration but with the suspension fully extended I cleaned off any bonded on dirt on the bags and inner white mount to prevent it grinding into the rubber. 2012 TDV8 Vogue (L322)

I don't think I dropped the strut when I disconnected my airline.
If I remember right I used a stubby 12/13mm? spanner quite easily.

Replacing just the front air bags was straight forward on mine and much cheaper than replacement struts.
I made sure the lower bag was pulled down over the seals and the retaining clip fitted to keep it in place.
The upper seals for the strut inner rod did not leak once the upper nut was snugged up.
Apart from handling the weight of the strut, it was an easy job. Not as difficult as I expected.
If the dampers are good why replace them? Of course, if you are paying for labour, it may work out differently. Forty years of progress. 1972-2012