Helping subscribers to renew (rather than create a new subscription)

Hello everyone,

Happy New Year!
I hope everyone had a relaxing holiday season
- for those of you where it is just starting, I hope there's not too much work when you get back

It's the New Year and subscriptions are up for renewal

I have a (probably) fairly standard Membership Pro (OSM) "setup":
There is a menu entry for new subscriptions and current subscribers can login and renew their subscriptions.

Has anyone found a way of NOT displaying a Joomla menu if a user is a current subscriber (in a Joomla - "Registered" sub-group)
OR
Linking a new subscription to a renew if the user is logged in.

Let me explain:
on b-l-s.lu
I have a Membership menu
- This links to "New Membership" ( b-l-s.lu/membership/new-membership )
and "Membership Resources" ( b-l-s.lu/membership/members-resources )

The "New Membership" shows a Membership Pro view=plans&layout=pricingtablecircle screen
The "Membership Resources" is the login screen to access the renewal/profile edit/etc.

My users do not all have the habit of loging in to renew so many just apply for a new subscription - and are refused because their e-mail is already used.
- This can't be avoided and I deal with it via e-mail.
However,
some members login but still use the "New Membership" screen to get a new subscription - rather than renewing the existing one.
This works even thought the e-mail is already in the system (probably because they are logged in???)

My question is:
- How do I force users who are logged in to renew rather than create a new subscription?
Is there a way to NOT show the "New Membership" screen but instead a "Renew Membership" screen, if they select the menu item "New Membership" and are in a particular Joomla "Registered" sub-group?

The complication is that not all Joomla (Registered) users are OSM subscribers.
- So, these still need to see the "New Membership" screen.

Any ideas?

Many Thanks,

-Graham S. Jarvis-