How can I locate the cavity between my house and my neighbours?
Answers: Never heard of houses have a cavity wall between two houses, cavity walls are used on external walls mainly to stop moisture ingress, unless they started using them on unusual builds (lets face it the regs own gone a bit daft haven't they).
My house has a 9" solid wall (2 bricks, no cavity) between mine and subsequent doors, the three external walls are cavity. Most houses I know just hold one or two bricks/ blocks between the two houses, I have never hear of a cavity wall between the two.
If I am wrong and you do have a cavity wall between the two buildings after 'boy boy' gave a pretty devout way of finding the cavity, using a drill.
Addition - If you are only just after finding the boundary, surely your among your deeds will have a plot layout on them showing where on earth the boundary is, I know mine gives exact measurements.
If you do not enjoy a plot layout/ boundary drawing, get within touch with the manor registry who will have it adjectives on record and should know how to send you a copy.
I'd be fundamentally surprised if your house has a cavity wall, especially if it be built in the 60's.
first it depends on how antediluvian your house ..and as you have not told us we will enjoy to guess you do have one ...assuming you do enjoy one mark a drill near some tape 125mm down the drill ..5 inches contained by old money ..drill away till you grasp to this mark and you are surrounded by the cavity ..as the last bit go in it will move about easy ..later you will know you have arrived