I think this may be the original version.....

An old Range Rover came over the hill,
Driven by the Gypsy Davy,
It rattled and it clanged and it popped and it banged,
And it frightened a little old lady.

CH: Hardy-do, hardy-doo-da-day,
       Hardy-do, hardy-day, etc.

He'd towed his caravan from County Kildare,
And parked it near Campsea Ash,
He'll tarmac your drive or cut down your trees,
But he'll only take payment in cash.
(CH:)
A fair young maiden came over the lea,
And Davy found her quite fetching,
He showed her his home with its milk-churn of chrome,
And his metaphorical etchings.
(CH:)
He promised her this and he promised her that,
She promised him plenty of the other,
But things went wrong like they do in folk songs,
Now she's going to be a mother.
(CH:)
The next time that maiden came over the lea,
Where was her lover so pure -o?
He'd done a runner, and he spent the next summer
On a building site in Truro.
(CH:)
So all young maidens, take a warning from me,
And don't let him string you along,
Don't give him a thing till you're wearing a ring,
Or you'll end up in a folk song.