Hi
we are still involved in the Building trade, but take no active part in the running of our company.
I can’t say definitely that the Lc500 convertible needs a bigger windbreak, but I had fitted in both of my last XK Convertibles a windbreak similar to the one you are showing and found them great and will fit one in my new car as soon as I can find one. Lexus Preston are quoting £1000 plus at the moment but normally can be purchased from Accessory dealers in the region of £250.
Sounds like you are going to be busy, I just want to get away to our place in Spain and get back to lunching out in country pubs with the roof down of course, when the lockdown permits.
cheers
steve