I would challenge your assertion that this route is plagued with tardiness. Since the beginning of the year arrival is, on average, 21 minutes after schedule. 39% of the time it has arrived on blocks early. Yesterday, it was 30 mins early.

This past week has been very bad weather wise, which probably accounts for the delays.

Today, it is looking about 20 mins late based on the data received at 1315. LHR is having a very challenging day with arrivals regulations in place due to gale force winds.