Do u need "O" Licence?

A mate is thinking of buying a rigid lorry with lorry loader to move things around with.
It will not be used for business just moving old bangers to race with etc.
Will they need an “O” licence to run it or not as they are not using it for hire or reward?

If for private use and not commercial use then no O licence required

If over 7.5 tonnes GVW then a tacho will be needed and will come under full EU driver regs

skypilot:
A mate is thinking of buying a rigid lorry with lorry loader to move things around with.
It will not be used for business just moving old bangers to race with etc.
Will they need an “O” licence to run it or not as they are not using it for hire or reward?

Moving their own bangers or moving them for other people? If moving them for other people will they do it for free or will they expect fuel money?

Conor:

skypilot:
A mate is thinking of buying a rigid lorry with lorry loader to move things around with.
It will not be used for business just moving old bangers to race with etc.
Will they need an “O” licence to run it or not as they are not using it for hire or reward?

Moving their own bangers or moving them for other people? If moving them for other people will they do it for free or will they expect fuel money?

Private can accept expenses and remain non commercial

Commercial means to make or intend to make a profit

What has been posted is completely correct.
I would suggest that your friend contacts the traffic commisioners office to get written confirmation. There are a heck of a lot of police and vosa that are unsure about some of the regulations due to the complexity of them. But keeping a confirmation letter in the lorry could stop a ten minute check taking an hour or more.