Now don't let the facts get in the way of a good story.
BEA Interim Report No.2
The RTLU was found in its place in the fin and disassembled. An examination was performed at the manufacturer’s and showed that it would allow travel of the rudder measured as 7.9° +/- 0.1°. As an example, at FL350, this travel is obtained for Mach 0.8 +/- 0.004, corresponding to a CAS of 272 +/- 2 kt.
We know from the AOC positions that the aircraft was proceeding at M0.82 and at what seemed a constant GS of 467KTS. However, when changing to Alt Law the last valid airspeed data caused the RTLU to limit rudder angle to +/-7.9°. A higher level, e.g. FL362 would also provide the same CAS, and I am sure that HN39 will be able to come up with a suitable graph for higher levels.
In all probability the a/c was still at FL350 and had slowed slightly in "light chop". We don't really know, and the RTLU may be telling us something different, so is this another "red herring" or something that should be considered.