Peugeot 307 battery removal

[Terryhenry]

I have a Peugeot 307 (52 plate), and I think the battery is on its last legs.

Question is how do I get the battery enclosure off in order to get at the battery.

I can remove the battery cables, and think the enclosure is just clipped at the bottom, however it does not seem to want to come up over the battery

Thanks