You can order kit via a Google Form which is on the forum under club kit. If you have a login you can access it here.
The BioRacer website contains all the custom cycling clothing that is available. Short sleeve shirts are usually in stock.
If you don’t know what to order then here are some basic suggestions.
Standard Training Kit
Short Sleeve Jersey Prof Matrix + Bibshort Prof Lycra Elite
Aero Race Kit
Jersey Short Sleeve Race Proven Aero + Bibshort Race Proven Lycra