What is your recommendation on upgrading a Linn LP

There are many good tables these days, and Linn is just one of the favors available.

That said, do enjoy my Linn unite a bit. Whether the OP want to update a Linn is determined by how committed the OP is and whether the OP wants to spend $

My Linn is not a top spec Linn any longer but it does music well-
Here's my set up- LP12 w/Cirkus, Lingo, Trampolin, Ekos II, Arliv B and Kore

If I were starting from scratch I would look at a VPI Prime and if I had more $ to spend, an SME

I suspect it wasn't grounded properly. I've noticed excessive static with my tnt that manifests as surface noise if not grounded properly.

Replace the Linn with a VPI Prime / 3D atm. Nothing can be done to a Linn that will make it sound nearly as good as a modern design. VPI Prime with the 3D arm is probably one of hte better bang for the buck table / arm combos today.

Well, since the OPs 3 preferred options are all Linn-based I'm going to stick with that question and keep it relevant. ;^)

The LP12 has the distinction of being the (only?) turntable that can be built from scratch using readily available non-Linn parts. Not only that but there could be massive number of permutations possible through alternate combinations!

Lets look at some options -
- Origin Live motor kit (highly regarded vs more expensive options)
- "Hercules II" (mentioned earlier).
- Cetech sub-chassis (again very popular & relatively inexpensive. Not sure if this is available now but Linn are countering the aftermarket sub-chassis suppliers with their Majik (£300) & Kore (£750). Both are way cheaper than a Keel.
- RubiKon = aftermarket competition for the Kore.
- There is also the TigerPaw Khan top plate upgrade. Bit pricey so I'm not sure I'd entertain that one. I'd consider a "BooPlinth" first.

Speaking of the "BooPlinth" (a continuously NC machined bamboo variant) which the former editor of HiFi+ Roy Gregory was ecstatic with. Roy, you may remember, spent a fair bit of time in that capacity doing VTA "roadshows" to illustrate the benefits of accurate VTA (during a time when very few arms had this capability) using a VPI with Tri-planar. In fact Roy said in a recent issue of HiFi+, "It's been 30 years since I last owned an LP12 but all of a sudden I'm taking the idea seriously again..." such was the impression the BooPlinth made on him.
His review is an interesting read and he is convinced it is a real game-changer.

The BooPlinth is not the sort of thing you'll see heavily advertised as the 2 guys who created it barely managed to scrape together enough money to get them manufactured(!) - so not much profit in it (and certainly not enough for "payola").
It's not cheap at £1650 so some serious decision making required there... (but I know one or two folk keen on buying it already)

Finally there is the question of implementation. Getting a franchised dealer to upgrade the T/T with aftermarket parts on your behalf might prove difficult but there are plenty of skilled amateurs/pros, I'm sure, in your neighbourhood who might offer to help if required?
All the best, whatever you decide.

Well, since the OPs 3 preferred options are all Linn-based I'm going to stick with that question and keep it relevant. ;^)

Suggesting a better option is completely relevant don't ya think?