Did the complete 10 km circuit of Cardiff Bay this morning – now knackered! Not much bird-wise except aout 1500 Black-headed Gulls, but of interest there was a colour-ringed Redshank [with a second un-ringed bird] at the mouth of the R. Ely by Penarth Marina with the following credentials:
Upper left leg – orange above a metal ring
Lower left leg – yellow above white
Upper right leg – green above red
Glamorgan Bird Club 
That sounds like a lot bling for one small bird.
Possibly this banding? http://www.cr-birding.org/node/569
Yes Annie, there was a lot of colour ringing of Redshank by the BTO in the period before what was the Taff/Ely Estuary became Cardiff Bay with the closure of the barrage.