Completing the set...
Managed to get hold of an Airway manual on eBay, so the set's almost complete now! Turns out the metal brush is correct, it's shown in the manual - maybe it's a later manual to the one posted here by eluxomarty - it also shows componants for the 'Junior Service' - ie, a smaller bag, additional cord with on/off switch and carrying handle to convert the Airway into a hand-held machine. One of the unidentified metal rings is in fact the paper bag clamp.
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