Shipping charges will be around £1,000.
Import duty, V.A.T. and brokerage fees will add about 30% to the total cost of the machine, including the shipping charges.
As an example, if you pay £5,000 for the bike and £1,000 to ship it, import fees will add £1,500 to that. Your 5 grand bike has actually cost you £7,500...
If the bike is less than 10 years old, it will need an S.V.A. test before you can register it (about £1,000 or so, depending on what needs to be done).
Generally speaking, unless the bike is very rare or unusual, it is simply not worth the time, hassle and money.