It seems that Royal Observer Corps Material relating to the Isle of Wight survives in the Hampshire record Office, in Winchester. Go to
www.hants.gov.uk/record-office and type in 36M96 in the Search Catalogue Box.
It's clear from the ROC veterans site that Hampshire ias where the bulk of ther UK ROC records have gone (c 1855 items).
This should provide some interesting information, of the days aerial activity with times, directions, identities of a/c's etc, but much legwork is required. This might well solve problem of AAA shootdown vs RAF claim for the Recce 109.
best
ChrisG