Yes, the enforcement costs can be added to the CCJ sum. And interest can also be added for the amount of time the sum remains outstanding.
You mention the CCJ has been transferred to the high court - high court enforcement officers are very effective so you should recover the money. The transfer fee is £66.
If not then there are other methods and you have up to 6 years to enforce from the date of the CCJ. The options are as follows :
1. Apply to court to order they attend a hearing and confirm what they can pay. You do this by filling in and sending form N316 with fee of £55 payable to HMCTS:
2. Instruct court bailiffs to attend and collect. Fill in and send form N323 (https://www.gov.uk/government/publications/form-n323-request-for-warrant-of-control)
A fee of £77 is payable (if you sued online) or £110 (paper method) payable to HMCTS.
You have already done this - you can apply to transfer the CCJ to the High Court so that you can use the high court enforcement officers (who have far greater powers than county court bailiffs including seizure of goods to sell at auction and forcing entry to premises). The following company can do this for you and they add their fee to the CCJ sum: https://www.courtenforcementservices.co.uk/services/ccjs-transferring-high-court/
3. If he is employed, apply for attachment of earnings order :
£110 fee payable to HMCTS.
4. Apply to freeze his bank account (if it is in credit - this only works on one date though) and the court orders the funds to repay the CCJ :
£110 fee payable.
5. Apply for a charging order on his property (if they own it) so the money is repaid when the property sells. You can also apply to force a sale :
£110 fee payable.
6. Apply to wind up their company if you sued a limited company and they owe you £750 or more:
£280 fee and £1600 petition fee is payable
7. Apply to bankrupt them if they owe £5K or more :
Petition fee of £990 and court costs of £280 are payable