I see you've made your decision, but to add my bit - a capillary based temp gauge would always read low unless you found a way to compensate for the temp loss along the length, pressure loss along a capillary would be less significant

I'm 6'4" (33" inside leg) and son 6'7" both fit ok in 300tdi 110. I find it a little cramped on RHS with door bit close but head and leg room fine. Could be different for you depending on leg / back length

I had maxxraxx on a previous car, really secure, just about to get the stepped version for my 110. Would whole heartedly recommend.

What was the outcome in the end? Just got a 300TDI 110 and after 5 days got the same symptoms. It had a new clutch fitted at Mr Clutch 12 months ago so still has warrantee but don't want to get caught out with "the part that failed wasn't covered so that's another £500 if you please". It has...