Some short backstory: Me and my partner moved into a rental flat (England) which was very unclean. We took a lot of time cleaning it ourselves, whilst exchanging many emails with the rental agency. The tenancy agreement clearly states that the property would be clean to a professional standard upon moving in, so we asked for financial compensation in lieu of a professional clean.
Eventually the agency agreed to compensation, but with the stipulation that the property be returned to them in the condition of being "professionally cleaned". This is a divergence from the tenancy agreement which states that the property should be returned in the condition we found it in.
My question concerns the enforceability of this new stipulation, given that "professionally clean" is so vague as to imply that a single speck of dirt could require money being subtracted from the end of tenancy deposit, and this agency is known for being exploitative when it comes to deposit negotiations. We are very hesitant to accept this clause for this reason, but we still feel we are owed compensation. The latest is that we have counter offered to accept the compensation without this clause.
Our next step if our complaint breaks down would be to take this issue to The Property Ombudsman.