http://www.parcelmonkey.co.uk/just re-found this place used them in the past and it works out pretty cheap for moving bike parts about the country next day delivery
i got upto 30cm cube and 12kg for £9, they pick up at your door and drop off [well dhl do but its 1/4 the price than going direct to DHL for some reason]
just thought id pass it on, makes buying parts from places you cant pick up from more sensible priced - i got a harley 4-speed gearbox posted overnight to me a while back and it was pretty cheap to do