In article ,
David Hearn writes:
What do people recommend? Should we connect our guttering (assuming
it's possible) or keep separate? Is there a real chance of damp due to
the gap, or is it best to keep as-is?

Like others said, keep them separate.

A join between two different makes of guttering is always
something prone to leak. Also, it makes the length of
gutter to expand and contract much longer, rather than
the gap being an expansion gap. The fall and position of
the two gutters might not be correct to join up at that
point anyway.

I formed a piece of lead to direct any water which comes
through the gap into one or other gutter.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]