OP - It needn't be too painful.
'Incorporating' just means converting from a sole trader to a company.
If you buy an off-the-shelf company just make yourself secretary and your son sole director. Give your son all 100 shares ( I think this is ok, there used to be a requirement to have more than one shareholder but I think it's gone now).
This means your son now owns the company. Your son doesn't have to pay you, but if your business has substantial assets, eg, tools, equipment, premises, and you give these to the Company you could be in trouble for hiding these from your creditors in an IVA or Bankruptcy. However if your son already owns all the stuff. . .
Don't forget as Secretary you have statutory obligations such as filing accounts. Get all the details from
www.companieshouse.gov.uk, otherwise it's nothing a local small business accountant shouldn't be able to sort out for you.