I don't really think bocking could be classed as a sport. Certainly it's sporty, sporting, sport-like. But the definition of sport encompasses rules & regulations, boundaries, officials and some sort of scoring system. And it's usually competetive. ...The term "lifestyle sport" may apply. A large part of my dissertation was on lifestyle sports.
AAAAaaaaanyway... Have you considered purchasing the bocks and keeping them at a friend's house? Especially if you have a friend who is also interested in Bocking, as you could let him/her use them in return for holding them for you.
You could even split the cost of buying them.
Make sure it's a close, trust-worthy friend though! You don't want to lose them.
Actually how old are you? I don't want to be corrupting youthful minds by telling them to disobey their parents! lol.
Respect your parents kids!