Yes, but before the default is added to the Equifax file, a default notice must be served:
• no default notice required by s87 (1) Consumer Credit act 1974 has been sent.
• Service of a default notice is a statutory requirement as laid out in sections 87,88 and 89 Consumer Credit Act 1974. Section 87 makes it clear that a default notice must be served before a creditor can seek to terminate the agreement or demand repayment of sums due to a breach of the agreement. therefore without a valid default notice, I suggest the claimants case falls flat and cannot proceed and to do so is clearly contrary to the Consumer Credit Act 1974
• Failure of a default notice to be accurate not only invalidates the default notice (Woodchester Lease Management Services Ltd v Swain and Co -  GCCR 2255) but is a unlawful rescission of contract which would not only prevent the court enforcing any alleged debt, but give me a counter claim for damages Kpohraror v Woolwich Building Society  4 All ER 119
so, no default notice means the default record on Equifax is unsubstantiated...