Hi Mikel and Zach,
Thanks so much for taking the time to reply. First time I needed to post on the forums and your answers were both extremely helpful and provided the answers.
To help simplify the cookies I used this js library https://github.com/js-cookie/js-cookie, which made it a bit simpler to set and get the cookies.
From there, run a jquery check on startup to see if the cookies set, and if so seek the part of the master timeline required.
Again, really appreciate the help, and the warm welcome to the community.
Cheers
Adam