Could be much harder to find in the UK and Europe and we have a surplus of them here as not many people have an interest in some of the British items they can't actually use. And there aren't many live Bren guns here.
Another example from a different vendor is the metal chests with twelve Bren magazines. Price for the set, complete with NOS grease is $41.95US which is up from the old price. Several years ago people had them for $25 per chest with the magazines and they were only lightly oiled and ready to use. I've seen them sell for ten times as much or more in OZ and the UK.
Link below gets you to Numrich and the cheap Bren magazines with chest. Initially it shows a single magazine but scroll down for the set which gets you magazines for half as much as singles.
http://www.e-gunparts.com/DisplayAd....hrSuperSKU=&MC