Is there a way to tell without searching through the calendar to find the start date and plan?
That would be very useful. If it was marked on the calendar it would be great. I was trying to compare rides I had done before I stated a base plan and which were after. Had to find the start date of the plan and actually remember it when looking at the TSS graph in the calendar. Anything that requires memory is going to test me 
Sorry, scrap my previous post. I have been into my account and now see what you mean.
Other than scrolling I don’t think you can see. I think they are planning to make this visible on the TSS chart in the future.
Colour coding would be nice to make it clear really quickly
I was missing this as well so I started adding annotations at the start of each week for a little text box to show what week I’m on for my run plan and my TR plan (separate boxes with different colors for the run and bike). Of course this doesn’t work well for older plans unless you go back and do the same thing.
Simple feature request here. Add the name of the plan your on On the top of pages on the website. Would be very helpful to not have to search for it.