I used to live 12 miles away, and can certainly say it's well worth a visit. As mentioned above, the Purple Emperor are out, and have recovered well from last years abysmal year, and the Storks have expanded their population massively this year, more than a dozen nests with chicks, so definitely worth seeing, the young will be getting close to fledging. There are always Whitethroats, Flycatchers and lots of Green Woodpeckers too. Fabulous place. Also worth a visit is Warnham Nature Reserve at Horsham. It's especially good for Kingfishers at the moment.