A development. Having copied my email to local Councillors, someone from Strategic Transport has responded to to tell me that they have baseline information:
"As part of our Active Travel budget, we have a rolling programme of data collection for walking and cycling activity at a number of locations on the transport network, including Middlewood Way in Macclesfield. We also analyse open source data from the Active Lives Adult Survey and Active Lives Children and Young People Survey, as well as from apps such as Strava. "
I actually interpret this to say that they don't, in fact, have any viable baseline data. The open source data appears to be related to the whole Borough, Strava is unlikely to catch much utility cycling and the only survey data they have relates to a shared use path that does not connect to the town centre in any meaningful way. I feel an FOI request coming on although I have asked for more details.