Tony Bloor asked about mites and strips.
 
My understanding from a lecture just last week by Dr. Nick Calderone of
Cornell, is that approximately 50% of the adult mites will be killed in the
first 48 hours by the strips.  The remainder will be killed over the next
several days, but the percentage is difficult to determine as the kill will
also include those emerging from cells.
Yes, your mite infestation is very low.
I have not heard of mite resistance in the UK.  That doesn't mean it is not
there.  If you leave the strips in for the recommended length of time you
will get a 99% kill, if you do not have resistance.  It is not 100% only
because some mites seem to escape the fluvalinate.  Unless resistance is
present, even those 1% would be killed upon exposure.  However, at the end
of the 6-8 week time, the amount of chemical on the strips is very low.
Keeping them in the hive beyond then will eventually lead to resistant mites
as the chemical load on the strips is not enough to kill them, allowing them
to build a tolerance.
I hope this helps.