I applaud Scalextric for releasing the protocol and I've spent a happy couple of evenings experimenting successfully and will probably integrate a few cool features (throttle rumble, throttle limiting etc.) into my own setup that uses an Arduino and 3rd Party RMS currently.
However the current frequency of the Timing data (Slot/0x3B0B) notifications is quite limiting and would probably prevent use of the BLE route by many RMS as their sole timing data.
Currently on ARC Air I see notfications every 300ms - And hence 1 for each car(lane) every 0.6 second
For ARC Pro with 6 cars its still 300ms per notification and hence 1.8 Second for each car - which equates to quite visible lag on the ARC application between crossing the line and the App updating with lap data. If there is a route back to firmware/software developers .... a significant increase in this frequency or create a dedicated characteristic per lane so each could be updated on the 300msec interval would make it much more appealing.....