Title deeds appear wrong - how to proceed

[RunsABit]

We want to convert our single-storey attached garage but planning permission has been paused because the boundary line on the title deeds is showing the garage width to the neighbour's boundary wall to be 1.7m, when in reality it is 2.8m.

Do we need to engage a surveyor, instruct a solicitor or can we approach Land Registry ourselves? Any advice on how best to rectify this please.

has the council paused the planning permission? If not, then who? I'd go back to the council or whoever, explain the problem and ask them what they will aceept as proof of the error.

I had a situation a few years ago. On my plans I owned a part on my neighbour's ground and on his plans he owned part of my ground.
We agreed to a sensible boundary line and drew it on a plan which we both signed. I took it to the land registry in Edinburgh and they ammended both sets of plans. As far as I can remember there was no cost for this.