3"clay water supply

[toucan]

I've been asked to try and sort this mess. 3"clay gravity water supply from stream/spring to two houses on edge of Bodmin Moor. It is about 12-16" below surface. Who ever did this repair dug a trench down slope to allow water to run off. White area is clear silicone. It is still leaking slightly. No one knows where the source is so I can't shut off supply to make proper repair. I could take a chance and go swimming while I try and square cut pipes each side and fit new 75mm insert with rubber couplings. Any suggestions on cutting clay in wet conditions. chain cutter -will this work on small bore clay. Is it possible to adapt a cordless and make it waterproof. Not something I've done before. Alternatively I'm thinking of wrapping existing repair with Fernco water activated resin pipe wrap. Has anyone used this kind of repair tape before. I'm assuming it may not work without stopping leak temporarily.
My reservation with this is it may harbour bacteria.

 

[snowhead]

The pipe from the chamber to the nearby 2500ltr storage tank is 32mmMDPE.
The tank is 2/3rd buried, top is visible in the picture, farmhouse in the distance.
White pipe to the right of the tank is the overflow back into the gulley.
Then the 750mtr run to the house is 32mm mdpe.

There are filters at the house, but weren't any when Son bought it 10years ago.