Vindication of motoring group checking Volkswagen Golf GTI's rear end (8)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

POLO (Volkswagen) G (golf) ~I (last letter of GTI) in AA (motoring group); my last car was a GTI. Sadly, I never loved it as much as my old Toyota Echo…Or, my appallingly unreliable Mazda 929.