So, as OP and in response to various questions: -
My allocated seat was 2A (no business class on that plane) but I was permitted to sit anywhere (I chose 1A).
I had a safety briefing, but I told them what they were going to say before they said it, so we had fun.
On boarding, my bags were taken from me and was told to go and 'chat with the flight deck crew' - and they were very welcoming.
After take off, the four CC and I talked for the whole flight whilst I guzzled some very nice BA freebie food and drink. I was even offered some bottles to take away with me.
The most bizzare thing was walking off a plane on my own and through deserted domestic terminal at Heathrow.
I could get used to it.
The reason was that the plane had to be in London for the next morning, so was positioning down and they put it on the schedule for sale to see if anyone actually paid them. I did and got lucky.