Cool, that should do you proud mate
As it has "Bluemotion" in its name. Does that mean it's the free or damn near free road tax?
I reckon you'll see low to mid 50'smpg easily enough Nick.
In my experience, the more outrageous the mpg claim from the manufacturer. The more you have to knock off.
A claim of 55mpg usually equals 17%-20% less in reality.
Where as a claim of 80mpg will probably need 27% knocking off before it becomes realistic.
A big part of why that's the case is that the manufacturer's are allowed to quote mpg figures from an engine running on a test bed not turning the wheels of a car. Plus the engine is being put through its paces by a computer not a human being on a commute to work.
If the Golf runs a timing belt not a chain. Ensure it's been replaced. Ideally you want an invoice showing the part & labour for fitting it. Not just an easily forged stamp in the service book.