Well superficially, that article implies that the tube web spider
might be the one to worry about since it is allegedly quite
aggressive. In reality it has been around in the south at least for a
good century or so and seems to have integrated quite well. There are
several in the dry stone walls around my garden and they haven't been
a problem.

The false widow does give a painful nip, which can become infected or
cause an allergic reaction, but it is hardly dangerous unless you are
particularly sensitive. I've been bitten by one a couple of times and
in comparison to a bee sting it is less painful initially, but more
irritating over a longer period. The bite leaves a pair of tiny scars
that take a year or two to fade.

False widows have been in S. Devon for a number of years and although
by no means common, they do appear to be on the increase. Up to 10
years ago, they were quite rare and only occasionally found around.
In recent years I'm a bit more wary about pushing foliage aside if I'm
wearing short sleeves because there's usually one lurking and a
concerted search can often reveal a few.