Anytime!
T-Shirts are available through the link below at redbubble.com
At the moment I apologise for not physically having any T-Shirts other than the one I wear as a demonstration to Makers Markets.
T-Shirts are still being considered as to whether they will be physically stocked and will be added accordingly.
For now please enjoy the Artwork link to T-Shirts and other clothing
https://www.redbubble.com/shop/RobertBarkerArt+T-Shirts?ref=search_box