Just thought I'd add my experience (as a debutant) of the keyhole method.
First of all, thanks to Canonite and others for all the useful info on this subject.
Had a bit of bother removing the filter box but by levering against the battery box, it came out ok.
Next snag was removing the battery box. The rear two torx screws came out ok but the front two were stuck. My torx bits are part of a 1/4" drive socket set and I could feel the extension bar twisting. Luckily, I had a 1/4" to 3/8" adapter and removed them with the 3/8" wrench.
Throttle body removed ok but then I had to nip out and buy a pair of snipe nosed locking pliers to release the hose clips.
https://www.toolstation.com/irwin-vi...-pliers/p51419
Now, hats off to others who have been able to get their hands in there with a wrench to undo the mounting bolt but no way I could do it. Maybe you have to remove the engine lifting bracket ?
Anyway, using the 1/4" socket set with extensions and universal joint, I was able to reach the bolt through a gap in the manifolds.
In the picture below you will see the 1/4" drive taped together with masking tape to stop it falling apart in use.Other items include a miniature inspection light to see what you're doing and various bits of bent wire to help guiding the socket onto the bolt. The magnetic retrieval tool and/or grabber came in useful when inevitably you drop something into the "V" .
The curved tube came ok as did the main thermostat body and greasing the seals on the new item with Vaseline, ensured a(relatively) easy installation.
Later, I cut the old unit open and dropped the element into a pan of boiling water and sure enough, it didn't move.
For me, this was a very tricky job but got there in the end
