Thank you to Martin for some instructions. Copied here for any others with similar issue: Open the alu cover to ease the tension on the spring. Lift out the 90deg bent end of the spring from behing its plastic chassis tag – use pliers with a firm grip. Take off the metal bracket over the spring. Take out the spring. Note how the spring rests on a small glider with its curved outer end. Now you can take off the hinges, alu cover etc. Successfully done in about 15 minutes.

Good job! And a great looking machine! A little too much damping grease - the cover should open a little faster and smoother. Martin

Thanks Martin Yes it is slow. I was too scared to wipe any away in case I took too much.