Prevent Multi-site : Site Title from being changed after signup

Hi.

Does anyone have a bit of 'code' that will stop the user of a 'multi-site' Site from changing the 'Site Title' (from within 'Setting/General/Site-Title area), after 'signup' please?

i.e:-

Permanently freeze the first registered Site Title!!!!!!!!!!!!

Thanking you in advance.

Regards

johnv