IMO once you have bought the fluid (Circa £10) and changed for £30-£40 labour (half hour at cheapest rate £60-80 Independent labour) I would just let VW do it.
It will be on the invoice, chances are properly done using a vacuum bleeder ( ie drawing the fluid through), you might save £10 getting it done elsewhere.
What is a £10? Spend the £ and get it done with the service IMO.