On 26/12/2018 10:35, ARW wrote:
On 25/12/2018 13:07, GB wrote:
On 25/12/2018 12:52, Dave Plowman (News) wrote:

Sounds like a use for one of those self levelling laser thingies. Got
one
from Lidl earlier this year and have only used it once - but was very
useful. Not sure how well it would stand up to be thrown around in
normal
pro use, though.


It sounds like a job for one of those tape measure thingies. Measure
inside and outside from some fixed point like the window sill. It may
not be spot on, but it won't be out by 12".



That would have meant putting down the cans of beers we had just opened:-)


Measure thickness of wall.

Drill through all but last 40 mm or so.

Poke a length of metal pipe into the hole and use a
metal detector on the unbroken surface to find the
location to confirm measurements.

If any discrepancy, have another beer, or some strong
coffee to counteract previous beers.