Update

So, the temp agency doesn't know why I was let go either, but suspect it was due to my having been off sick the week before (even though I'd brought in a doctor's note as requested.) Not sure of the legality of that, but suspect attempting a wrongful-dismissal action would be too much money and effort to be worth it. The agency is sending me on an interview for another assignment tomorrow (though it's telemarketing, so I kind of hope that they don't take me and that the other place they sent my resume to does.)