Here's a link to the place I bought my plants from. The place is called Debenham in Suffolk and I bought the decorative barrel collection because my pond is so small there were enough plants in that collection. They're very nice by the way, so it's an added bonus if I got some free wildlife (now you've reassured me that the frogs will be OK).
Water plants, Native Pond plants, Aquatic plants, Puddleplants

Right, this is what I found around the postcode you supplied and the address of the aquatic store in the above link.

Around you: There are three open expanses of water approximately three clicks to the SE of your address, and another expanse of water the same distance in the opposite direction.

Around the afforementioned aquatic store: Quite a rural location, however there isn't a great abundance of open expanses of water around this neck of the woods. The nearest 'lake' is a about a click to the northeast.

Crazy huh?

Quite a mystery. My stickleback seems to have vanished, so now I'm wondering where he's got to rather than where he came from. Maybe he's just hiding though? I'll let you know if he reappears! It's a shame really that my little foray into fishkeeping only seemed to last for about three days.