Thanks everyone, some useful thoughts and suggestions for me to ponder.
I always use a decent helmet (Hebo Zone 3) and gloves and have invested in some proper Sidi Trials Boots (only really because I was used to the comfort of Sidi when I had road boots for the R1).
I have looked on eBay for ideas and quite like the look of the EVS RS8 knee protection. I've looked at most things from individual protectors for arms, legs, back etc. as well as the mesh type with built-in protection and back protector. There's just so much choice it's almost confusing beyond belief.
I agree with the 'confidence' that protection can give you (even if it's all in the mind). I'm also mindful that ill-fitting equipment can be as dangerous as not wearing the stuff.
I'm hoping to attend my first trial on the 8th December with Mansfield Maun club so I've got a bit of time to make a final decision. Either way, I think it might be the white or yellow route I attempt first. I've only been practicing in a mate's field with some off-cuts of logs (I'm going over stuff about one to two feet high at the moment) and would prefer to enjoy my first trial instead of scaring myself stupid. It's quite ironic that 180mph on a race-prepped R1 didn't phase me at all, but going over a two foot log at less than walking pace appears like a mountain to me at the moment