Places like the Trafford Centre and Manchester Airport have their own jobcentres , as do many other large retail shopping centres .... the Lowry shopping outlet probably has one too , and maybe even Manchester Arndale ..... sometimes it's better just to go and have a look at what's advertised in their windows , or see their staff for job vacancies.
You could also try the stores on the Regent Road retail park ..... such as TK Maxx ...... or the Triangle shopping centre , near exchange square.
Some places also advertise jobs on gumtree ....... and other places such as Dominos/fast food joints etc are always after part time delivery drivers.