I’ve had 2, but my current Blur LT is getting through lower shock bushings at a fair rate. I’ve tried using a heavy duty kit and supplied plastic bush it includes (from TFT) but that one still only lasted a few weeks.

Is a 2 part bush like the one below likely to last longer?

http://www.santacruzbikes.co.uk/shop/product/fox-bushing-kit-igus-22×8-wreducers/269

I think they are meant to be better, think that is what is on my current one.
Dead bushings from my experience come from moving back ends and something getting in there and wearing them. Back end flex doesn’t sound like an LT. Bends/twists or anything like that?

No, back end is stiff (new BLT with bolt thru), and I also install and remove with a proper tool. I will have a proper look at the shock eye next time, maybe it is worn a little (but hope not…).