I often have overlapping reservations on the same day, even on the same flight, with no issues, but that's on fully flex tickets.

I did have a H class departing at 1015 and an E class to a different location at 1230 for a few days earlier this month.

One of the benefits of being one of BA's best customers is the ability to do this. If a few chasers are put out, so be it.

We know from the great gold devaluation of 2013 that (despite protestations of tesco-lubbers) there weren't hoards of golds keeping the availability low by this scheme. Given there are far fewer GGLs it's something you shouldn't worry about.