As someone who has had the (dis)pleasure of flying both -436,-300 and -500 with BA. I can confirm that the two tilt options are available on the -436 and on some of the -500, but not all it depends on where they came from...............along with all the other differences which the -500's have! e.g pressurisation, trimmers, nav boxes, radios, MCP's. Shall I go on?!