Thankyou for taking the time to respond. I should have made my initial post clearer (but was trying to keep it brief in case I was wasting people's time).

I have been able to configure proxy support and tested it by referencing a proxy that does not require authentication.

Unfortunately the 'production' script will not sit as I do in a DMZ but in a 'production' network where the only Internet access is through the aforementioned and troublesome proxy.

I use "production" in a sense that colourfully described would see me branded as horizontally challenged-ist.