The message
from Lobster contains these words:

Right now we haven't even decided between condensing and vented - from
reading around this it's not clear to me which, if any, is the more
economical to run?

The figures on this are skewed. Vented ordinary driers may use less
energy to dry a load, but that energy then leaves the house as waste.

Condensing driers retain the heat in the house.

Depending on how you use your drier this can make a large difference to
how much it costs overall. If, like us, you only use the drier when it's
cold outside then you'll probably save by having a condensor. If like
our neighbours you use the drier when it's a dry breezy sunny day then
you'll probably be better off with a vented.

--
Skipweasel
Pay no attention to that man behind the curtain.