www.p4d.co.uk is a firm local to me but they seem to consolidate with UPS and work nationwide. It seems like a good deal to me and we've done all sorts with them - food parcels to my godson when he started Uni (they made at least 3 attempts to deliver) and have shipped clothes around to help manage with complex itineraries.

I suspect this model is copied elsewhere so see if you can find something local, but otherwise it's only something like a £2 surcharge.