I unscrewed the hinge and the back plate fell down inside the machine. this meant taking off the top (3 screws) and the back cover (about 15 screws) - I could then get the fallen back plate easily but you can't reach to where it fits 'cos of the drum.
To fit the backplate in to position I dangled it from a piece of wire (tied on with masking tape) then managed to press it in position with my hand in the rubber seal (as answer 1) and enter the screws. Pulled the wire out, leaving a bit of masking tape there forever....
For info my model is a WD61 Hotpoint Aquarius 1100 Washer/Dryer but probably exactly the same procedure. In 10 years of heavy use I've fitted brushes 3 times, a new door interlock, a new pump, a new heater element and re-solded a coroded connector, plus now a new hinge. All bought off eBay for pennies and fitted on instruction from this site - MAY THANKS.
Chris Brown
March 2007