How do I protect/unprotect macro buttons?

In my first post (Password Controlled Cell Entry and Subsequent Actions), I asked for help in using VBA to control usernames and passwords via Excel buttons. The attached file is the most up-to-date version.

As I need the macro buttons to control users and validate passwords, thus allowing staff to insert their signatures, everything is LIVE. When I have used sheet protection, the macros don't run. All the buttons are active, but I want to restrict the user to only the buttons that are applicable to them. I want to force them to click the right button(s), dependant on who they are and what they are doing.

1. The "Float" sheet has to be populated with today's date, two float seal numbers and two office staff signatures.
2. This sheet then needs to be opened by retail staff when the floats are inserted in the tills and numbers verified with two sets of signatures per till.
3. At end of day, the tills are emptied and two seals numbers entered and numbers verified with two sets of retail staff signatures.
4. The following day, the "Float" sheet becomes the "Cash" sheet and the cash out seals broken and numbers verified by two office staff.
5. Data is then entered by one office staff and then checked by another office staff signed/co-signed accordingly.
6. Money is banked, with banking seal already verified by office staff, and signed/co-signed accordingly.
7. The completed form is then printed and filed with appropriate receipts.
8. Finally, the "Cash" sheet is copied to become the "Float" sheet and data cleared apart from required data shown in step 1. The sequence then repeats ad infinitum!

I've not got the above procedures in place yet but that's the aim. The main thing is making sure that the sequence is followed and protected against inadvertent errors.

Your help would be greatly appreciated.

Many thanks in advance, especially to royUK for his sterling assistance thus far.

BTW: Enter "Manager" for User name and "m4nag3r" for the password when the workbook opens. This gives you full access/control.

Cheers, DrEcosse