Help me schedule the long run in my week

I might suggest that it has a lot to do with how well you can recover from the Long Ride on Saturday. (IE. Will it impact your ability to hit your intervals on Sunday)

It seems to me that you correctly identified like workouts and swapped them. (Both Intervals and the LR are "Hard" and so should in theory be interchangable)

If your set on creating some separation between your long ride and run, than this seems reasonable to me. If your concerned, you could do some more gerimandering of the schedule and try to get a recovery day before the Intervals.

FWIW: I did my long runs early in the morning before work mid-week in my plan and did my long ride on Sunday. (Were I would traditionally put my long run) It worked well although it did make for a long day at work

Maybe it's just me, but when choosing a plan to follow it would seem the planners had a reason for putting the workouts on certain days. If the plan is not followed as written, the results may not be the same. There are a vast assortment of plans. If you want to separate the long run and ride, maybe you should find a plan that is scheduled that way.

Perhaps a reason for doing long ride on Saturday, long run Sunday is to make sure you'll get used to running long on somewhat tired legs. Plus it may force you to run at a slower pace, which is typically not how many people end up doing their long runs. Hammering out a long run at too fast of a pace makes recovery more difficult and can affect subsequent workouts.

In the matter of switching the days - long run Sat/Long ride Sun - it may be easier to ride long on tired legs.

Yeah I understand the point about a plan being structured a particular way so I have been reluctant to faff around with it.

The good news is it's a long plan so at least I have plenty of time to try it and see if one options seems to work better for me than the other.