Hi,
David wrote:

Yes, I must confess that there is no lightning arrestor installed as of yet!

it was mainly a product of my Scots heritage getting the best of me.

Sounds familiar. Actually a lighting arrestor isn't worth much,
and I'd suggest a large knife switch directly between the lead-in and
ground.

Your present antenna is ideal for broadcast reception since, as has
been mentioned, most antique radios were designed with this sort of
antenna in mind. Extending the lead-in to the basement will simply
make it work better. The vertical part of the lead-in catches most of
the signal. Keep it as far from power lines and noise sources as
possible. If your ground is now farther away, you may lose some
efficiency; my ground is a driven well in the basement.

On short wave, things are different. I've used my inverted-L for
short wave too, but never compared it directly against another
antenna.

Cheers, Alan