Dave Fawthrop wrote:
[...]
Have you got the wrong type of tow bar? My present Witter tow bar
has room for any hitch without problems.

If you read the OP again you'll see he's asking about making a tow bar, he
doesn't have one ATM so it can't be the 'wrong type'.

As far as making one goes, it's probably illegal in that it won't be
certified as complying with the relevant regulations - I know this is a DIY
group, but in this case I'd stick to DIYing the fitting of a proper one.

Dave