Thanks all for the advice and encouragement. I took it back to the shop today and incredibly couldn’t get it to replicate the trigger sear not engaging. Typical! That being said, the amount of force I was encouraged to use was a lot more than I had ever used before, and as a big bloke I wasnt messing around with it before. It’s just a characteristic of the rifle so Needless to say they wouldn’t take back a rifle which wasn’t exhibiting any fault.

Agreed, I was lucky with the underlever flying back both in respect of keeping all my fingers and not breaking the rifle. Lesson learnt.

All this being said I still have to put an incredible amount of force into cocking this tx, much more than the only other over ever used and it isn’t fun. So...
I got home and stripped it down fully, degreased and re-lubed, that made no difference although I have introduced some twang annoyingly. I determined how the latch rod engages the trigger and safety and cleaned both mechanisms but again no difference. The only thing that made it marginally easier for both trigger and safety to engage was to lighten the trigger weight but I was verging on having a hair trigger.

Has anyone please got experience of fixing this non fault?