Take a look at the Better fitness website.
Various types of membership which spans across Swindon, the Link Centre, Oasis, Dorcan, Croft and the Haydon Centre amongst others. There are different types of memberships, my boy has the Gym and I have the rackets membership which allows me to book Squash and Badminton pretty much as many times as I want in a month (limited to one booking a day).
https://www.better.org.uk/leisure-centre/swindon