cutom banner printing for shop

[sydeny black]

Hey guys, Newbie here, I've got myself an electronic store and was thinking about replacing my shop banner as it had been a long time, time, with a new custom design I have in mind. I had my old banner done from one of the local shops, and when I enquired, they don't handle such custom designing and printing. As an alternative, I started searching online for companies who dealt with such custom printing services and came across one. Has anyone approached them for their services? Could someone help and advise me on what to look out for when hiring such companies for professional work?