Martin wrote:
and tar and creosote.

Not necessarily. I've built a new railway sleepers bed at the back of
my house. Got 2 sleepers, 7 quids each, untreated and new. Got them at
my local timber merchant, Moores on Upper Chorlton Road in Manchester.
If the OP fancy a ride from Merseyside, that's where I got mine. But
having them delivered is far easier )

http://cjoint.com/?jmnduMYMTl