There appears to be some problem especially with the 5g tubes.
Until a month or so ago the pharmacy were saying there was a problem with the 5g and supplying the 3.5g instead
But now can't get the 3.5g tubes anywhere and the 5g tubes just ooze ointment out everywhere; you can't stop it 
I get the impression they've now run out of 3.5g and are just supplying the known problem 5g tubes.