Hi,
It /seems/ that the UK arrivals times are being shown as UT/GMT but are being labeled as BST -which I take to mean British Summer Time.
Which gives the flights arriving one hour earlier than they will do in reality.
I think 
For example, the website says:
British Airways 214
BAW214 · “Speedbird”
Boston Logan Intl (KBOS)
to
London Heathrow (EGLL / LHR)
Terminal 5
Arrival
Scheduled: 08:05AM BST (+1)
Duration: 5 hours 29 minutes
Wednesday, July 30, 2014
BA say the scheduled arrival is 09:05 BST
The website also gives (I guess as a result) an implausibly short time for the flight - where one would expect about 6 hours 30 minutes.