Guys, I have done what you suggest. I also had a Simmonds roof on my 2002 +8 and know how wonderful they are.
Problem is (and this is what AWSC pointed out) in order to have one of their hoods I would first need a pair of screen pillars, I was quoted £1300 a side! Plus the hood job so closer to £5K and not economical. As Phil said better to sell the car and buy one with the hood you need.
Problem is I adore this car, just been for a trundle that turned into a 75 mile drive through some local villages, amazing how hard it is to find a pint of milk.......
Probably easier to buy another Barbour jacket and put up with the rain on my glasses.
BR
Colin