BBC Radio 4 'Report' programme aired Monday 2000 provided a good summary of the Ash Story So Far, with interviews with some of the key players from CAA, NATS, etc.
No mention, however, of any organised attempt or directive about what examination of aircraft should be done post-flight.
Assuming ash damage is cumulative and ash forecasting still depends on modelling. Any available quantitative data could be used to forecast the impact on specific engines and also to calibrate the ash forecasting model.
I'd hoped that evidence from aircraft that MIGHT have had an ash encounter would be considered valuable enough to be collected in an organised way. But it seems not.