@Richardvwr; I’d suggest that your brother also considers the insurance implications. UK insurers would consider these changes to be pretty major modifications for the purposes car insurance, so it’s likely they would be looking for a sizeable increase in premium.
It would be worth your brother checking with his insurance company on how willing they (or any other insurer) would be to cover his car If you go ahead with this, and what the likely cost of insurance would be.
It would be worth your brother checking with his insurance company on how willing they (or any other insurer) would be to cover his car If you go ahead with this, and what the likely cost of insurance would be.