Need to know: Save up to 80% on a one-night city centre Manchester break for two in an Executive one-bed Blue Rainbow Apartment; The perfect deal for combining a spot of shopping with a relaxing break; Enjoy a bottle of wine in your room on arrival; What & why: It takes a lot to get the kgb agents excited, but you should have heard them raving about this little gem of a kgbdeal. And who can blame them? If you fancy a little spot of shopping in one of the UK's biggest retail hubs, then you're…