d-Mannose is often very helpful and worth a try. It is thought that it works better in a alkaline environment - so you can take it along with sodium citrate if you wanted, or try the fizzy tablet one I also suggested. If you are going to take cranberry, that must have at least a PAC 36 to be effective and works best in an acidic environment, so the two don’t really go together.
If you suffer from frequent uti’s, it might be worth trying Hiprex (methenamine hippurate) which is available (very expensively!) OTC, but your GP can prescribe it.
Oestrial cream (Ovestin, and similar) is very good IF you can tolerate it,but many women get horrific burning with it - others, none at all, so it’s worth a try. Otherwise, Vagifem or eString.