Any luck so far, Pete / @orionstars? We are having similar problems implementing ERPNext at our mobile device repair business.
There is not a smooth “flow” in ERPNext for dealing with a given customer’s device or timepiece as they go through the bookin process, and I don’t see an easy way to customise it without diving into code, which I will probably have to do.
Would appreciate in tips in getting it to work for you.