@KKC1 - Wow, that must have been an unwelcome headache and a future worry.
My client's security peeps have responded saying (politely, but firmly) that the web-app server is vulnerable to BEAST, POODLE, etc. and pointing me to their
'recommended' standards.
I have had to remove all my client's branding from their web-app!
As far as I can tell from my Google searches, TLS 1.2 seems to have been supported by browsers for at least 7 years -
TLS Protocol Compatibility - so I don't know which browsers (of any consequence) would be locked out.
I feel the writing is already on the wall for keeping the web-app here. And I don't want to expose either my client or myself to the consequences of a successful attack.