As we're not a unionised site I'm looking in to creating this role to aid in empowering the workforce. I was just wondering what training those who already have such roles, provide/recommend? NEBOSH Cert to me is OTT as an introduction and maybe a IOSH/CIEH might be more suitable.

There is an IOSH 3 day course for safety reps, my organisation has delivered this. I have also run tailored courses for reps. PM me if you want more details.

We are non unionised too.

We give all our ROES (we are multisite) IOSH Managing safely
This gives them a good understanding of the realities and avoids "bar room H&S".
The real keen ones are encouraged subsequently to upgrade to NEBOSH cert.

Another fresh pair of eyes is always of use and demonstrates to the workforce we are serious about H&S.

Not safety rep training BUT we've just changed from RoSPA to British Safety Council and now get 100 one day level 1 courses from them as part of the membership package. Only problem is muggings here now has to deliver the training ;)