Or so I though. Well it isn't hard to get the plane tickets.
It takes some luck, I think, to find affordable plane tickets (like 600$/person)
and flying into 
Manchester
is not as popular as London, so tickets to Manchester are at a premium.
We flew into Gatwick and took the train to central London... carrying luggage
for two, a spare motor, all my tools, spare parts and leathers. Pack
Light. The London Underground at rush hour packs more helpful and
patient people than any subway in the US. Strangers helped us carry
suitcases packed to the limit up stairs and into the trains. It was
fun.
VirginTrains took us from London to Macclesfield near Manchester were
Don Leeson lives and hoards Suzuki vintage racers. What's a train
you ask, well I had never riden on a train before (no the boston subway
doesn't count) so the 3 hour trip from London to Manchester was fun, very
comfortable and anything was better then carrying my luggage around.
Don picked us up at the train station and had already collected the bike
from the Manchester airport.
Indeed all the difficulty in obtaining a license paled in comparison
to shipping the bike. I ship scientific equipment 
worldwide
quite
frequently at work and didn't expect the trouble that was to come.
It all worked out, but there were a few moments where it looked dicey.
After getting a few quotes from motorcycle specific shippers, who normally
ship street bikes for vacationers, I was disappointed by their prices (roughly
750$/ each way). Basically I need to ship a 200lbs box, so the cost
shouldn't be much more than a plane ticket and the crate wouldn't expect
free drinks. Emery
Worldwide was the most helpful, had competitive rates, and were located
at the Rochester Airport. The first problem was that they will only
accept packages from businesses, the recipient on the other end can be
an individual, but the shipper must be in business. We have a family
business so it worked out, but this may require some creative planning
otherwise. Delta air freight does appear to accept shipments from
any individual, so it may be worth trying.
After carefully packing and crating everything, I found out that no batteries, no gas tanks, and no oil can be shipped via Emery. The RS was dry, but the tank was used. If the tank is new then they will ship it. I ended up unpacking the crate in a warehouse at the airport and removing the gas tank. Realistically no one actually checks inside the crate, but you sign some very official looking forms declaring that there are no explosive / hazardous materials in the crate. The US postal service had no problems shipping the gas tank directly to Don's home address. Also we checked the gas tank in our luggage for the return trip, something Brendan Morgan does on his yearly trips to the UK to buy cafe racer parts... no problems with the airlines.
The
customs requirements will require about an hour of your time, but no real
hassles. You must file out a form of registration (proving that you
own the stuff, and that it will be returned to the US) and an invoice of
what is in the crate. Serial numbers, lists of parts, etc.
The more details, the less likely they are to bother you. Since my
bike was completely disassembled there was quite a list of parts.
The more official and the more organized you can muster, the better.
I think dealing with customs on anything other than a real race bike might
be tricky. They are looking for thieves trying to export stolen goods.
A couple of important points to remember: You could collect the crate yourself, but you'd need to very carefully plan the timing, discuss this with the shipper. Also ensure that the return journey is either pre-paid or is freight collect (ie: paid when you pick it back up at home.) The British cost to ship to the US, can be higher than the US to UK, so prepayment is important to get the best rates. Make absolutely sure that all the documentation possible is in the hands of the person picking up the freight in advance. My crate was stuck in British customs for 3 days at 20 Pounds a day storage because the paperwork hadn't made it to Don's house in time. Pack it like every guy who's ever operated a fork lift is pissed that they have to work while you're going on vacation. Plan ahead.
The roundtrip air shipment cost about 750$.