Just wanted to say thanks for all the advice above. Sorry it's been ages, it's degree show time at work so it's mega busy.
@cheekysnaker I had/have already bought a sus corrected rigid fork with anything mounts. It's got a straight steerer so I bit the bullet on the boost spacing, which is why I'm considering a full new wheelset.
@M_V Thanks a lot for the link to the Hope 135x12 TA hub. I think I'm going to go down this route, I just need to find an axle to suit (I haven't had time to do much digging here.
"Keep your money in your wallet to spend when you need to. That’s future proofing!"
This is perhaps the best advice, but I kind of want to spruce it up a bit. Haven't done anything to it since buying it off here 5 years ago. It would be of use too, both as a more heavily off road bikepacking option over the gravel bike I got recently, and as a second bike so my partner and I can go camping together.