Yes, it seems so.
Here in Ireland RBS (yes, I know, different group but bear with me) own Ulster Bank and First Active, and the situation is the same as the TSB/Lloyds scenario you mention. A couple of weeks ago they announced that First Active is to close pretty much all branches, and this after many years working in proximity to each other.
The current crisis is going to be the catalyst for wholesale changes in high street banking, and I'd put money on TSB either disappearing as a brand or being merged, the net result being branch closures on a huge scale.