Regarding the burr-combing, it seems like some colonies are predisposed to
make a mess of things like that.  Buckfast bees IME are remarkably
reluctant to construct much burr comb, even with 9-fr in the brood nests.
Certain other colonies will go nuts constructing quite a lot of burr/brace
comb, and will clog up a queen-excluder but good.
 
Dr. Morse has often recommended putting excluders on the hive roofs when
not in use, where the sun will melt off some of the wax, and give the roof
a certain amount of waterproof wax coating.
 
I'm wondering about the Australian lid with the underlying mat  --  in an
intense honeyflow aren't some colonies apt to cram the lid full of combs
and honey??  (Above the mat, I mean.)
 
A number of  commercial lids or inner-covers I have seen in use have a 3/8"
- 1/2" rim on the underside.  Can't say why -- the top-bee-space (the
"standard" in North America) then ends up way too large, and the bees can
plug that all up with burr comb, = pain-in-in-the-neck.  Same goes for
framed q-excluders with a bee-space on both sides.
 
We have some brand-new hives we built, purchased from one of the MAJOR U.S.
bee-suppliers, and were surprised to find that only a scant 3/16" or so
space is provided above the frames, *and* the inner covers are FLAT on the
bottom.  There is barely a bee space over the frames.  To put terramycin
patties on, we have had to invert the inner cover.  Several colonies built
and filled big patches of burr comb in the space, before they would touch
the undrawn plasticell foundation right there in the brood chamber.    Go
figure.
 
Very swarmy year, from all accounts, around here.  Wonder what it's been
like in other areas.
 
Kindest regards all,
 
J. Govostes                    Freeville, NY