Aeroman - I am beginning to think that taking the Aero down as is and hoping for the best is a good plan; just wanted it in great conditions!
Good man.
Would love the shower cap for that purpose - as it happens I am with my parents in Virginia Water this weekend so could easily drive over to get it on Sunday (and would love the opportunity to see your car) - if you really will accept no money, could I take you out for a drink to say thank you?
The only issue this weekend is the Aero Club trip to Silvestone. I need to find out what time we need to be there on Saturday, as we spending the night in the area. The final GT3 race on Sunday is planned to finish at 16.55 pm. By the time we get out of Silverstone and get back it might be late. Where are you next weekend?
That shower cap could mean the trip down through France in an Aero with a leaky roof can be contemplated (even if it will clash with the blue paintwork

)
If it clashes too much, just pass it on to somebody with a green car on your return.