My current certificate has been superceeded by a more current edition but it isnt obsolete. With that in mind I can discuss electrical requirements and some advice to you. Maybe a few solutions to problems, at the very least liase with a current edition electrician to discuss requirements to do the job. Or simply explain to you, so you can ask yourself. If you have a business maybe its time to get that PAT testing done, Portable Appliance testing. At the same time discuss those other repairs ?