[Kevan]

Although I did the boolean work in Netfabb when I got home because:
a. It's simple
b. It's done 'in the cloud'
c. It's simple
d. Did I say it's simple

...I did eventually find a youtube tutorial how to use boolean in Blender and it did work after rebooting the software after I'd added a couple of addons

But it's not turned out too bad for a first effort - I must admit I like the Mk1 Escort style bubble arches, they'll get used on other cars