There are 16 regional VTTA groups across the country, and you join the VTTA through one of these. You can join whichever group you like, although to enjoy the benefit of local events you'll normally choose one where you live.
The groups don't have rigid boundaries, so there is overlap in some areas. If you move to a different area you can choose whether you change group, or stay with the same one. If you did want to change group you would email the secretaries or membership secretaries of the two groups - you can find their contact information on the group pages. Since groups set their own subscriptions you might find that your new group has a higher or lower fee. We don't make any adjustment for a mid-year change, you'll just pay the new amount on renewal.
Each group is effectively a 'club' affiliated to the CTT and your VTTA group may be considered your 2nd claim club, after your local cycling club, although if you choose you can have your VTTA group as your 1st claim club.
Some groups have their own website, and you can follow the link to their site to find out more about them.
Each group has a link below, and you can see there which part of the country they cover.