You save a lot less after paying import duties.

Do you pay import duties in the UK on items purchased for personal use? The situation is changing constantly in the US, but generally speaking you do pay duties only over a certain dollar amount in value if you intend to keep the item in country after importation (and a MBP would be over that amount), but it's a fairly small percentage (around $400 in duties on $3149 saved here). I'm not sure how it'd work in the UK.