In respect of a mortgage application, lenders will be focusing towards your credit conduct, history and affordability, not specifically your credit score. Specifically, whether you pay on time, how much of your limit you use (utilisation), whether you carry balances or otherwise any defaults, missed payments, or persistent debt.
Cash or cash adjacent purchases of this nature aren't likely to make a large impact on your credit score if this is a minimal use case. They matter in a different sense because they usually accrue immediate interest, to a lender this could suggest an on-paper reliance on borrowing cash which is undesirable, or an increase in perceived utilisation. This is not likely make meaningful dents in the credit score itself, but may present a query for certain lenders especially if there were an ongoing pattern and this were at scale (larger amounts or increasing amounts). In short, It is realistically not a deal-breaker on its own, but it may be questioned in the context of affordability if it forms part of a wider pattern of credit usage that suggests reliance on borrowed funds.
As an aside, I would investigate your credit history with other credit references agencies as they can differ. In your case Equifax and TransUnion, as not all lenders report to all agencies, difference weighting can result in different scoring across CRA's.
In terms of a mortgage application in a years time, it will be the credit behaviour from the 3-6 months prior that will be most heavily scrutinised, therefore if you are worried then it would be best to adjust these types of transactions ahead of that timeline so they aren't an issue.