This is explained at paragraphs 2-4 of the decision you link.
- There were two proceedings: a claim in the county court and an application to the Tribunal.
- The county court claim was transferred to the Tribunal to be consolidated with the application, and they were to be heard together. (Although, technically there should be no literal "transfer" or "consolidation"; the claim is always a county court claim, separate from the tribunal application. It is just that the matters are heard at the same occasion by inviting a tribunal judge to sit in their capacity as a county court judge. See commentary on City, University of London v. Vodafone Limited (2020).)
In that circumstance, Judge Nicol was sitting as both a tribunal judge and as a county court judge. This is possible because:
On 22 April 2014, the Crime and Courts Act 2013 Sch.9(1) para. 4 was brought into force, providing that judges of the First-tier Tribunal are judges of the county court and therefore able to exercise the jurisdiction of the county court, providing that a claim form has been issued and the matter has been listed for hearing by them.
Stephen Jourdan, K.C., "FTT Judges sitting as judges of the county court" (January 2019)
See also this previous Q&A where this was explained.