Transformers die cast figure help needed

Ok so there have been these small ( a couple of inches tall) die cast Transformers figures in my local tesco for ages now and I am thinking of collecting them they have loads of them but only 4 transformers. They have

Galvatron
Thundercracker
Prime
Hot Rod

Is there more of them out there and is this just one of the series that you get. A complete list would be great if any one has one or any pics.
Here is a pic of the Galvatron one so you know what I am talking about.
Thanks in advance for any help


Also I know they come with display bases but are the figures stuck in the pose taht they are all ready in or can you change them.