You need to look at the lease, & see what provisions it contains about the responsibility for doing work of this kind. I suspect it will say the leaseholder cannot do it without the freeholder's agreement, or words to that effect. You then point this out to the leaseholder & ask for his agreement to pay for the repair. (You cannot claim against the window cleaner because you do not have a contract with him - it is up to the leaseholder to do that.
If the leaseholder refuses topay you have no option but to give way or to start Court action. However, if the wording of the lease is unclear this could be risky.