On 27/12/2018 20:39, bert wrote:
In article , GB
writes
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".


The two halves of the old Forth Road Bridge were closer than that!!

In defence of the OP, there wasn't a brick wall between them