On today’s ride my rear shock seemed to keep loosing the air I put in it. I pumped it 3 or 4 times and after about 5 mins it was all gone again.

Will this likely be a simple issue or a bike shop jobby?

On another note I managed to kneel in a red Ants nest and boy are those little buggers fiesty…. Ouch

Sometimes just the valve core coming loose, tried tightening it?

Dunk it in a bucket of water, or spray with soapy water to see where it’s bubbling from.

As above the valve core is worth checking but if the air is escaping from the main shaft seal, new seals might just be all you need & are easy to replace.
Assuming it’s not new(ish), a full service would probably be in order, if the seals have had time to break down.

It’s a 2011 camber which I bough 2nd last year. To be fair it’s due a service.

It is my first full sus so I have no idea as to the mechanics of shocks.

When I put air in the first time the valve was a tad loose, maybe I didn’t tighten it up enough.

It’s fully safe to submerge it in water then?

I had similar with my Maverick shock. It was a slower leak than yours but I put it off for ages and kept topping it up. I eventually sent it off and it came back working like a brand new shock and it changed the feel of the bike. Don’t put it off, get it serviced.