The CSV that I have seen before can jump very high, I believe higher than my Doberman could when he was younger. We had a plank fence about 1.8m high too, no footholds, with about 3-4ft of concrete under the ground. We had a pool so those were the rules for housing with pools (so no kids can get in and accidentally drown).
Yet Lantis could escape once chasing a cat...
Not only the height of the fence matters but also depends on what and how the fence is constructed. If it is chain-link, it is easy for the dog to climb the fence.
Some people I know who do rescue work recommend that if you use chain-link, to make the top portion inward slanting so that even if the dog climbs the fence he cannot escape out the top.
- Jing
Edit: Also yes, bicycle fastener. I like WalkyDog bicycle fastener. It has a pull-absorber so you won't fall off the bike if the dog pulls. But I am in the US right now, maybe you can find one equivalent? It looks something like this:
http://www.thedogoutdoors.com/walkyd...ike-leash.html