Limited-edition Batman action figure set, mint condition

I lost my limited-edition Batman action figure set, mint condition, yesterday afternoon in Cardiff. It was still in the original blister pack inside a black presentation box with a silver arc logo, kept on a shelf by my desk. I last saw it around 3pm near the entrance to Cardiff Central Library on St Mary Street, after stepping out for a quick coffee and leaving my bag on a bench. The set includes Batman and Robin; Batman has a blue suit and a black cape, and the packaging has a tiny crease along the top edge and a 'Property of' sticker on the back. This item was a gift from my brother and carries sentimental value, so I’d be really grateful to get it back.