Thanks for your input guys, we're talking about an unamended initial clearance here.
The original question still remains unanswered: if, prior to getting airborne, you are given an "XYZ 1 Y" departure with a clearance to a higher level than the SID (as published) allows do you still have to adhere to any "stepped climb" restrictions?
So far we've had different answers from current Controllers at a major UK airport and the College of Air Traffic Control at Hurn.
Seems to be a bit of a disconnect here, leading to confusion in both ATC and the flightdeck and quite possibly Level Busts.