I got some 8mm Aluminium weld on barb fittings off e-bay for a couple of pounds each. My manifold is Ali as well though. It has made a difference to the running of the engine with the vacuum advance piped up for the first time. Im running R1 carbs on a 2.1 Pinto. The engine is much smoother across the rev range now.
If the air filter is touching the bonnet then perhaps an air scoop above it could be the most effective solution. You should be able to direct the air right where you need it. Nothing turns out to be easy, but keep smiling mate.
I had a Vauxhall Belmont many years ago and the same thing happened. The car had stood for a couple of weeks and the caliper had seized. Luckily it was while reversing up the drive.
I was quite shocked to hear about the couple in Scotland. It was on a major road near Sterling. If it turns out the guy died during the 3 days they were waiting then someone is in for the chop, or should be.
I did tell some of the local South Yorks area ish gang about this at the July meet last night. New laminated windscreen for my 3A purchased from Grassmoor Glass who are on Storforth lane industrial estate in Chesterfield. I took the old windscreen in as a template and left it with them overnight. The new windscreen was cut to size and all edges were rounded off. The total cost inc VAT was £39. I know this is only of use to anyone in the area but due to the very reasonable price I thought it worth mentioning.
I haven't got any wrap on mine at all (2.1 Pinto) but I have got some around the clutch cable that passes between 2 of the pipes. It been like that for the 13 years i've had the car with no problems. (so far).