If during this time you have successfully enforced a CCJ against a debtor then the 6 year period may not apply or provide your business with another 6 years to reclaim the outstanding debts.
Chasing a debt post “statute barred” is not advisable as it could possibly lead to a harassment claim against your company under the Administration of Justice Act 1970. And a business cannot issue a CCJ against a debtor once the 6 year "statute barred" has been enforced.