Do you mean Miss Jessop's Upright? Its a good variety, and tends to be a little more upright than the others. Rosemary is rather like lavender in that it does not grow from old, woody parts and tends to get rather woody and leggy over time, so if you want a green and bushy plant, its best replaced every few years anyway. It will not get as large in a pot as it would in the ground, but once you've bought the new plant, pot it up in something a couple of sizes larger than its original pot, then pot on as necessary.

Thank you very much for the replies yes I did mean Miss Jessop’s - problem with predictive text and me not checking !!
I think that variety looks nice and neat so hopefully better for a pot