Can a bailiff clamp a disability car that doesn’t belong to the debtor?

No

Bailiffs may only take control of goods only if they belong to the debtor.^[1][2]

Any vehicle displaying a valid disabled person’s badge because it is used for the carriage of a disabled person is exempt goods.^[3][4]

^{[1] Paragraph 10 of Schedule 12 to the Tribunals, Courts and Enforcement Act 2007
[2] See: Making a claim to controlled goods
[3] Regulation 4(1)(d) of the Taking Control of Goods Regulations 2013
[4] See: Making a claim to exempt goods}