Made it to Heathrow, landing just about 2 hours late. Missed 13:20 connection to BUD. Next flight at 18:25. I also wondered why my 7-hour flight was held. Given a £10 voucher and a"sorry." Kudos to BA gate staff at IAD who kept passengers well informed of the situation. Flight itself was excellent, with attentive and friendly cabin crew. First time on a 787 for me and loved it.
I assume this won't qualify for EU delay compensation.
Any recommendations on where to grab a bite in Terminal 3?