Well having read all the comments, I think that maybe you are now still at square one!!!
So many Fors and Against, at the end of the day, if you really want to give it a try, then just go for it, BUT!!!
Keep it simple, only buy a tractor unit, NO Trailer, because at this stage you have no idea what type of trailer you need,
and of course, you have no customers, So it looks like traction only pulling trailers for between £1.30 to £1.50 ppm.
Have a very close look at your costings and if your figures say that you can make a profit with you driving, then give it
a go for 3-6 months and then re-evaluate your position, if not very good then sell up and lose a small amount or just carry on?
In the meantime, whilst you are working, you should make contacts with suitable companies whom would be interested in using
your services etc, and then you can buy a trailer to suit the type of work being offered.