I have to say that my recollection is that most of the clamour to ground Concorde came from "mid-Europe".
The plan is not to resume services by April, but to start validation flying then. Services should restart in June barring unforeseen problems.
Contrary to the suggestions that this machine is being rushed into service on a tide of public sentiment, the current mods have been in development since VERY soon after the accident. I don't know where this concept that the liners will be a problem because of structural flexing has arisen: 1. The liners are flexible and flexibly mounted and 2. In my experience the whole shebang aft of tank 9 (the forwardmost tank, at the apex of the wing) is bar-tight in the cruise!
It's a shame that the 'fixes' for 737 rudder hardovers are not so closely and verifiably tailored to address the failure modes.