Thanks both.
Just wiped it down with a clean cloth and tested it electrically connected but not fitted so I could see the plunger work , which it did.
Reassembled and tickover seemed fine , so pending a trial run I am calling it.

Postscript : tickover now fine. My gut feel is simply breaking and making the connector sorted mine out.
Googling the part number on the Air Control valve itself ( 228W8569S ) gave this , which visually looks identical , and if it plays up again for 11 quid is worth a punt. Has anyone else tried this part ?
https://www.autodoc.co.uk/ridex/814...lPitb_L7SYhLolaEF7y1Em-Ur_RoCszUQAvD_BwE

You could pay £11 or you could pay substantially more to have the S&S name associated with it!