Ceiling Hoist Engineer

This job is on an ad hoc basis. I have a pair of Test Valley Mobility ceiling hoists which are still very much operational powered directly from the mains via a transformer. One of the hoists is over a hydrotherapy pool in my bathroom. I'm looking for a service engineer because the original servicing is no longer available.

Having tried to replace the hoists I have discovered that the new hoists are only battery-powered and that the suppliers are reluctant to install due to concerns of corrosion in the charging circuit from the pool humility. I'm therefore looking for an alternative solution which enables me to continue directly powering from the mains.