Lay a nice thick blanket (I use an old cellular job from the 1970's) over the top flat section of the bonnet. Open both bonnet halves so the blanket is sandwiched between them and tie the knobs together across the top to hold it as a single unit. Use some gaffa tape to hold the hinge blocks to the bonnet
Then you can take the screws out and lift the whole thing up and out of the way. Make sure you have a space prepared to put it down, I stand it on its rear end on another blanket.
