There are quite a lot of nice places in Hemel...ie. the original "settlement" before the new town was built and, of course, parts that have been added on since.
As for the under 16/17's night in Ignite - I remember a friend of mine going there and having her drink spiked. Luckily she managed to escape unscathed. I've never actually ever had any trouble at Jarman Park, although I've heard countless tales of shocking misdemeanours and the like in said location.