C Grade - yes, likely referring to the action or amount of engraving.

Rigby had C Grade actions - all they were were Webley and Scott actions with less engraving - well, mine is anyway but like everything in the British gun trade, their are exceptions.

Sounds like a reasonably good buy.

Is it an ejector ?

Do you know if the action is a Webley and Scott Screw Grip action (or PHV-1) ?

Important question
Why are you thinking of waiting for another rifle ?

If this suits your needs / wants / requirements, go for it.
These type of things are few and far between.

If you are waiting for a bargain, keep waiting because all those I have known who wait for a bargain rarely find it while prices just keep going up.

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