If it's anything smaller than a trolley or bag, just use this address and drop it off at any post office:
Freepost RTYL-UYCX-ETEX
Stewart Golf Ltd
Edison Close
Waterwells Business Park
Quedgeley
Gloucester
GL2 2FN
If it's a trolley or a bag then email us at support@stewartgolf.com and we'll arrange collection.