I know for a fact that the Spitfire did have trim tabs on the airlerons for trimming but they could not be adjusted in flight. When the pilots lands he made his own corrections using a block of steel and a malet.
Small excesses of metal on the airlerons surface could be bent up or down to counter act any trim issues the pilot was having on his next flight, the problem would then hopefully be solved for his next hop.
Here is a video where a Spitfire is shipped form Duxford to the USA and it shows when they are doing the flight testing after it is rebuilt the pilot trimming it. Go to 40 minutes in. He trims it just after he lands. Sorry for any adverts on this video, it's a TV Channels on demand service.
Cheers
Mini