I suppose I should have clarified. When it is business to person (as opposed to business to business) online sales within the Single Market the selling business charges the same price including VAT to the overseas customer as they would to a domestic customer.
So if the advertised price in Italy is inclusive of VAT as it usually is over here for retail goods then this is what you will pay. The only extra will be the postage/shipping costs, which will have VAT payable on top at uk rate of 20%.
I’m not sure if Italian pricing includes vat as we do - for instance I believe the USA stupidly doesn’t often show all the various federal and state taxes that will be applied at checkout in the advertised price - but if not then you will have to add that on. Not sure of the VAT rate on shoes in Italy but the EU vat rates are, for fairness of competition reasons, deliberately kept similar across the 27 members plus us for now, so it will be around 20% I expect.