Thanks Rich,
there's no spring retainer at all, or any clips for that matter. There's literally the tube through the fan housing, cable to the throttle and spring over the top. Cable is held in place via a screw at the throttle arm.
I'll get new bits ordered today.
When the cable is detatched it doesn't quite fully close - but a light push with a finger sorts it, so I'd say either the spring in the carb is tired or the linkages are a bit worn maybe?
Thanks for the heads up on Carburettor Exchange, looks like an overhaul is in order :beer: :d