ok, problem resolved, and it wasn't an inibuilds issue.
Before purchasing I had another KDTW from flightsim.to installed and forgot all about it - it didn't show up in the Marketplace when I was checking for duplicates, it was just buried in the Community folder, why does everything have to go in the same folder?
So while I was starting my troubleshooting process to work out if I had a conflicting addon causing the problem I found it, deleted it and now the issue is resolved.
Thanks to all who assisted, you may now call me Richard Cranium!