Dear Prof Ab,
off the top of my head i would suggest:
- contacting the staff of/ looking into PJ's gigs at Evershot Village Hall (Dorchester):
https://evershotparishhall.org/band-on/hall-of-fame/, which by the way features Polly's mother, Eva, as one of the band promoters over the years. Pj did a "secret" gig there on 2004-09-19 ( i have no more info about it), then on 2007-11-18 she performed grow grow grow and was interviewed by BBC 2's Culture Show there (i don't have the recording saved, but i may have watched it in the past, honestly, i can't remember);
- On 2009-03-12 she did a gig with John Parish in Bridport Arts Centre and again on 2010-12-18 she performed there (both gigs are missing from my saved ones). You could contact the staff and ask about them
https://www.bridport-arts.com/about/;
- On 2009-07-25 she performed at Camp Bestival near Lulworth Castle ( i
do have multiple recordings of it, basically all from Youtube):
https://dorset.campbestival.net/;
-Looking onto the 2025 Dorset Music Awards (Original Music Awards)
https://www.lighthousepoole.co.uk/dorset-music-awards-to-honour-pj-harvey/ would be a great idea; she indeed won said edition and gave a speech on 2025-01-17 ( which was recorded and shared by Romario on his Youtube channel,
https://youtu.be/20yuKNcWIU8?si=9bdtKHLMAalEgYX3);
- I do know she did other "secret" gigs and, if i remember well, multiple charity events, can't remember many details though, if there were any in the first place. Matter of fact i think most of them didn't take place in Dorset. Take this point
grano salis;
- Maybe you should contact someone from The marshwood Vale magazine (
https://www.marshwoodvale.com/about-us/), they interviewed Eva Harvey:
https://www.marshwoodvale.com/people/2010/06/eva-harvey/.
I would say that's all for now, i'll add stuff if anything else comes to my mind, and hopefully other gardeners who are way more knowledgeable than i am will intevene. Cheers.