How long does it take for DHL to deliver a parcel from London to Belfast using DHL Next Day Delivery?

I bought a replica Chris Fehn Slipknot mask for Halloween off Ebay for �30. The shipping cost �6 and was DHL next day Delivery. The seller posted it on Wednesday and it is coming from London to Belfast in Northern Ireland. Today is Saturday and it still hasn't arrived. Anybody know what day and what time of day it will arrive at? Thx