Driving the 350 today, I noticed that under 3mph the holding brake comes flying in bringing the train to a halt, in reality this doesn't happen until the train gets down to 0.5mph. Also when braking, initial brake percentage on Desiro's will give around 5% on the brake whereas the train is showing over 40%, almost feels like it's driving in 3 step braking rather than percentage braking that Desiro's have. If there's any info needed on how the brakes operate on Desiro's I'll be happy to help as I drive them IRL.
I just posted about this myself. It seems the position of the CPBC/user interface is not in sync with the actual % of brakes being applied, so it becomes all or nothing basically. Also means we can apply a very unrealistic level of brake force if we went full service. Didn't know the holding brake only comes on below 0.5 on those though! Kieran. P.s. The 707's are doing well over here