As per vikinger, you need to move the remote sensor down to the middle left third section of the box. It works perfectly with the existing Sky + PUC commands. Just took me a little while of moving the sensor around until I found the new infrared receiver placement on the new smaller Amstrad box. Its almost impossible to see.
You'll be very pleased with the upgrade. Better looking on screen text rendering for the menus, quicker menu display and to my eye, HD movies look a little sharper.
As an aside, I've not yet once had to perform a reset. My old Thomson box needed a reset once every 4-6 weeks.