As much as I sympathise with you and feel for your situation. If you choose to live above or below any kind of business you have to put up with what they offer. I don't think you will get anywhere with Lewisham Council as the business is up and running allready but hopefully you can build a relationship with the gym and come to a good agreement. I know if it was me I'd be more than happy to try and resolve any situation. BTW congratulations, hope the birth goes well!