looks like the problem is the tree this side of the fence judging by the paving slabs and that from the trunk and leave looks like Ash . if it is thats your problem the roots go
for yards and are very strong will damage your drains as well that close to the house.

Both your tree and your neighbours prunus are too near to the houses, not much more than a metre away. Also the fence is damaged, the spread of the roots is about the same as the spread of the branches. The trees should be removed before any more damage is done.

you can see in the picture a big root heading under the brick wall.

I'd have both those trees out pronto.

Ash trees also grow extremely fast and extremely large, and have a habit of self-seeding all over the place - which is presumably how this one arrived.

There is also a seedling Sycamore growing on the roots of your Ash, this being another huge and invasive species. Both are quite unsuitable for garden use and should be removed.

id say at a guess you need a word with your nieghber about there trees to . im guessing yours may have come from there garden perhaps .

Thank you all very much. I now know what I need to do.

cool your welcome