That is what I meant, the physical measurement between the two properties, i.e. the centre line.
There are certain things which help you and certain things which don’t.
Once the fence has been in this position years or more then it can stay in that position provided it’s been in that position without consent or objection than that 10 years.
Although common sense would dictate that the boundary was midway between the 2 properties and that both areas with the same, strange thing happened when the Victorians were building houses. So although that would seem logical, it’s not actually definitive.
There is a straight line on the boundary on the title plan and that helps you also a 12 inch deviation on the plan would hardly be visible because of the scale of the plan. You will probably find that the line around the property is about 8 inches wide when you measure it on the ground and therefore a 12 inch deviation is unlikely to show up but that wouldn’t stop you making the point.
If the line of the chain fence carries on and hits the house 12 inches over from the centre line that helps you as does the fact that there is no logical reason dogleg unless some other buildings have been removed at some stage that accounts .
Whilst there is no definitive evidence as to where the boundary should be, if this were to go to court it would be decided on the balance of probabilities. That means that it hasn’t got to be absolutely certain the fences in the wrong place but it has to be more likely than not and it would appear that in your case it’s more likely than not that the fence is in the wrong place. The only potential problem you have is the length of time the fence has been where it currently is and if the neighbours come up with some proof that it has been there than 10 years but probably enough to defeat your claim to be in the wrong place.
If you have house insurance, check the policy because some policies have legal expenses cover that may pay costs if this were to go to court. If this were to go to court the loser could easily face a legal bill which could be as much as £10,000 or more. reason, if I were your neighbour I would probably agree that the boundary should go down the middle. It might sweeten the pill a little if you agree that you would pay fence to go down the centre in the correct place.
This is not something that your solicitor would have picked up in his enquiries unless the responses did say that one of the boundaries had been moved which would seem to be unlikely.
Can I clarify anything ?