Hi guys - this is a somewhat difficult question to answer because it
relates to the United Kingdom/Great Britain rather than continental
USA but if you don't ask ...
I am a male of 42 years of age and have just retired having wound-up a
small family software business. I'm too young to sit around and do
nothing and so, as I love driving and have some experience of
luxury/performance cars, I wondered if anyone knew of any companies in
the UK that offered a service by driving/delivering cars for private
customers or garages either to other parts of the UK or further afield
in Europe. I would love to deliver cars within the UK and Europe and
then just find my own way back home. Any help on this one would be
really appreciated.

Hi cbowring-ga:

Yes, that's quite a difficult question - but very interesting! :-)

Here is what I've been able to uncover so far: 

The vast majority of vehicle moving services I was able to find use
trailers of various sizes to deliver cars - NOT what you're looking
for.

It appears that people who do what you are proposing are called "Trade
Platers". There's a great article on a Baptist minister who does this
at:

http://www.suite101.com/article.cfm/hitch_hiking/56918

This article includes names and link to companies that employ Trade
Platers. The two most promising seemed to be:

European Vehicle Deliveries
The Galleria, 
Unit 8a 180-182 
George Lane, 
London, E18 1AY 
Tel: 020 8532 9696 
Fax: 020 8532 9292  
General Information: questions@e-v-d.com
Vacancies: jobs@e-v-d.com (web page at
http://www.e-v-d.com/Job%20Opportunities.htm)
Website: http://www.e-v-d.com/index1.htm

Ace Vehicle Deliveries
Tel - 0208 903 3000   
Fax - 0208 795 0047
Website: http://www.acedel.co.uk/
Jobs: http://www.acedel.co.uk/jobsat.htm

Next, I tried the UK-based yell.com business directory at

http://search.yell.com/search/DoSearch

in their "CAR & COMMERCIAL VEHICLE DELIVERY SERVICES" section at

http://search.yell.com/search/DoSearch?screen=VAL&state=AMB&companyName=&businessType=CAR+%26+COMMERCIAL+VEHICLE+DELIVERY+SERVICES&location=&Searchbutton=Search

I was able to find two companies that appear to provide a service
where the cars are delivered by being driven to the customer's door
(within the UK). I would suggest calling them for employment
information (at the contact information I've provided).

Plateline
Delta House
Delta Commerce Centre
Old Wareham Road
Parkstone, Poole
BH12 4QN
Tel: (01202) 717800
Fax: (01202) 722345
E-mail: sales@plateline.co.uk
Website: http://www.plateline.co.uk/

Vehicle Movement Specialists
The Skill Centre
Limberline Spur
Hilsea
Hampshire
PO5 3LF
United Kingdom
Facsimile: 023 9266 5657
webmail@vehicle-services-uk.com 
website: http://www.vehicle-services-uk.com/

I checked all the companies in that yell.com directory that have
website links, but none of the others seemed to be what you want.
However, there are many other companies listed that do not have links
to websites. You might want to try calling a few of these if the other
leads I've provided don't work out.

Afterwards, searching on the term "trade plates" (which seems to be
key), I found the following:

http://www.miles-associates.co.uk/job.htm 

which is an employment website offering the job called "Vehicle
Delivery" (about 1/4 down the page). The brief description says:

"To collect and deliver all types of new and used vehicles across the
UK using trade plates. The work is suitable for either full or
part-time work and is paid according to distance covered. You are also
paid any waiting time that is incurred and there are bonuses available
for out of hours and timed deliveries / collections"

I hope this gets you started on this new adventure! If you require any
further clarification, please let me know.

(Some of the successful) Search Strategies I used on Google:
"trade platers"
uk "business directory"
vehicle delivery "trade plates"
"trade plates" luxury cars

Thanks. 

websearcher-ga