Well, after ages of paralysis by analysis, I finally got down to it.
I'd had some work done on the TX (titanium piston) and I felt the trigger needed some readjustment afterwards.
The guy who stripped and fettled my trigger initially had cut a window in the block to show sear engagement.
The advice i got from him was that dry firing CD was ok.

Initially I thought I'd do all the adjustments with the trigger on the action but this involves much cocking and firing.
Much safer/easier with the block off the action, so off it came.
Those 2 retaining pins are a b*gger to knock out/return aren't they?
Tight tight tight, and rounded ends so the pin punch wants to slip as you tap away.
Off the action and wind out the 1st and 2nd stage screws until nothing engages.
Wind the 1st stage screw in until it just holds.
I'd thought about just having a 1st stage trigger, without fully realising what that meant.
You get the trigger cocked and safe but no sensation of stop with the trigger prior to the sear slipping.
Not nice.
So, wind in the 2nd stage screw and, lo, a stop appears.
Slacken off the pull weight a fraction.
Back on the action and back in the stock.
One tiny tweek to the second stage to remove a fraction of creep.
Cock, remove safety, whack butt, whack pistol grip.
A long first stage, then a stop you can feel and bump up to without the gun firing.
No floppy trigger when you back off the shot.
Tiny bit more pressure and away she goes

Time to stop now, perfect for me.
I'm grateful for your advice folks.
Now to shoot some groups.