We have the Saracen lock and are quite happy with it. It's easy to put on. As far as recommendation goes you never know how good they are until someone attempts to remove it but it does claim to exceed Gold Sold Secure standard and is cheaper than the ALKO locks.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.