You won't get a student loan if you've already got a degree - they base it off whether you've got the qualification already, not whether they gave you a loan for that qualification. Like Ash said, there are exceptions for NHS funded courses, and there could be one or two other odds and ends like that, but broadly speaking if you have a degree and want another one, you're on your own.
If you've already got a degree, is it worth seeing whether you could do a Masters? Even if whatever you want to study now is something very different to your first degree, you may be able to do a conversion Masters; it would cost you a lot less than doing another undegraduate degree; it wouldn't take as long; and as a higher qualification it could look better than having two undergraduate degrees...