A very desirable collectable! I saw one at an auction a couple of years ago and I think it went for more than £400. The Haenel V repeater was a standard pre-WW2 model V with the addition of what John Walter called a "Cox-type pan magazine". The Haenel V, made from about 1925, rifled in both calibres, was basically a longer stocked version of the model IV, which was a direct copy of a BSA Lincoln Jeffries pattern underlever. Here's an advert taken from a 1930s Haenel catalogue.