In all, 10 unique bird species seen, but some very commonly seen birds were not seen in the hour from 3pm to 4pm. I twice tried to submit my results to the RSPB, but on both occasions it told me there was an error. On another page it said I had submitted the results! Rubbish!
For the benefit of anyone who wants to know, these are the birds spotted in our back garden 1500-1600z:
Black headed gull 1
Collared dove 3