Only once have I travelled out of Euston on a train with tilt disabled. It was a 221 to Chester.
It was also a day when the live train speed was shown on the internal PIS*, and it was noticeable that the 110mph PS speed limit was closely observed.
The underlying PS 110 limit has not materially changed since BR days, and extends over the vast majority of the route.
It's the EPS speeds which added the complication (assisted by TASS).
The new MU speeds will not be TASS-assisted.
*Why doesn't that speed display happen all the time, if the trains have the capability?
It's quite common to see the live train speed on high speed trains abroad.