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If someone offers you Revo other than from either Revo themselves or via one of their officially approved agents, stay well away! It won't be genuine or supported.
I don't recall it ever being as much as £700 - More like £550 and worth every penny imo - Great aftersales support and reliable software.
Going for a cheap remap from a less established VAG specialist tuner and saving what? £200? £300? - Not worth it - Any issues could cost you far more than what you've saved.