when I learnt to use Perl in the early 1990's I did so out of necessity and by looking at a very limited pool of other people's code which either didn't include strictures or, if it did I didn't notice

That will be because it didn't exist in the language back then. I think it was around 5.002 when it was introduced.

I have experimented with turning on use strict; and got frustrated at having to declare variables before use so ended up not bothering. It sort of slowed down the initial code development although, granted, it may well have speeded things up down the line had I persevered.

I don't see why it would slow down initial code development at all. Could you explain more?

FWIW, here is one of my recent nodes showing the benefit. And another one.