Air Con packed up on Citroen Picasso

[XMG5]

My Air Con has packed up on my Citroen Picasso. I've topped up the gas and watched as it vapourised, amidst loud hissing, into the atmosphere from a leak in the condenser.

I've been quoted £180 incl VAT from my local Auto parts dealer or £320 fully fitted/re-gassed/VAT/Labour included by a local garage.

Has anyone replaced the condenser themselves?
Is it a specialised job?
Does it require specialised knowledge?
Does it require specialised tools?

Any advice would be welcomed.