I suspect that 'Lady Boothby' is a hybrid of F. regia, which is about
as close to a 'vining' Fuchsia that you can get. 'Lady B' has been
doing the rounds for many years, although it has never been heralded to
the general gardening public before. I remember it as a lax-growing
shrub that dies back in a cold winter, but can remain almost evergreen
down here in the South West. It is undoubtedly very root-hardy and if
you can persuade it to retain the top growth, it makes a very charming
tall pillar from which arching branches cascade to display the flowers.
In cold parts of the country expect it to just about reach 1.6m and in
milder regions 2.8m or more. To my mind it needs to be admired from
reasonably close quarters since the very dark corolla'd flowers can
seem to disappear from a distance.

Fuchsia regia ssp. regia is rather more vining, although the stems do
not twine and need the support of neighbouring shrubs or trellis. It
is reasonably root-hardy in many parts of the UK, but like 'Lady B'
will be a tallish shrub with arching to lax shoots where it has been
cut back by frosts. The foliage is quite striking, being long narrow
and glossy. It promises all manner of exotic ideas of the flowers to
come, but they arrive as being a tad too similar to F. magellanica (to
my mind) albeit rather larger. I had it against an east wall here for
several years, but it eventually became crowded out. Here it ran on
for over 3m. in either direction and was often forgotten until a spray
of flowers appeared amongst other plants. F. fulgens 'Speciosa' now
does a vaguely similar trick, but with more erect growth, whopping
great pink-veined, sage green, heart-shaped leaves and seriously
handsome sprays of green-tipped, coral-orange flowers.