A couple of years ago I was en route to Lee on Solent from EGSF, with cloud forcing us lower and lower (eventually had to divert into Popham, but that's another story).
I called up Benson (this was on a Thursday), and asked for a basic service and MATZ and ATZ penetration at 1000'.
The was a short, startled pause and then permission was given with the additional information "traffic is a Lancaster also transiting our overhead at 1000'".
And there it was, to starboard, about a mile off, marvellous sight