Chrysolina beetle

Was picking some home grown chard and spotted this little iridescent beauty amongst the leaves.  As near as I can tell from google it is a Chrysolina beetle, but I can't narrow it down to exact species.  Candidates seem to be Dog Bane beetle, Mint beetle or Dead nettle beetle.  No sign of a "chard beetle".  Any experts out there?
Anyway, picked my chard, blipped my blip and left it alone to enjoy the rest of the afternoon :-)