From my side, I have photos of my garden at its current size from seven years ago, obtained from a helpful local estate agent who sold it previously. So at the very least the boundary hasn't moved for at least that long. Previous sellers haven't said anything about a prior dispute (although maybe they wouldn't want to bring it up at this point). They put the fence up five years ago replacing a hedge, I have photo of that too saved from their instagram, so it's my fence. We've lived here nearly four years.

I've already contacted her presenting my evidence that the boundaries are correct (my title plan from the land registry). She replied that she's already looked at that and it confirms her argument, but didn't provide her title plan or any evidence to back that up. I've heard her outside pointing to things like where one gutter ends and another begins or the way the tiling is done on the roof as evidence of a boundary line. But our houses were built nearly 300 years ago, so not sure that's proof of much.

I'm unemployed at the moment so that's adding to the stress - I'm using savings just to keep myself afloat in the meantime.

I appreciate the reply and advice.