UKC

I guess making water repellent really, but anyone got any advice for doing this?

It's an excellent light softshell, just be good if was a bit shower resistant.

Techwash then TX Direct, or Grangers, or something else?

Cheers.

Yeah wash and then treat with a spray-on. Nikwax do a softshell proof exactly for such a purpose, but realistically any proofer will do the job.

Tx direct will work, but be aware that it'll probably lose some breathability.

Hi mate, I have the same jacket. Got it last spring It is naturally shower resistant but it started to loose its resistance towards autumn last year, I washed with tk tech wash and then TK soft shell. It is as shower resistant as it was from new again now. 
it’s such a great lightweight shell. Great to climb in I love it!
 

hope that helps