PAYE can simply be closed with a letter. VAT deregistration takes 15 min online. I don't see how he can incur a hefty bill for this. Though, depending on how many months he paid his accountant, he may have to pay additional fee to prepare a full set of accounts. The OP can also keep the company dormant instead of closing it down if the OP is planning to trade again in the near future. However, if he takes the first available opportunity to work as an employee and switch back to contracting in the near future, it may become a concern with regard to IR35.