Set storage was always cited as a problem by those in the industry when they looked at the TC plans. But we are where we are. I think at one point I read that TC2 was effectively going to be used as set storage for TC1/3 but with itv moving in and giving TC2 more work that seems less likely. I’m guessing there’ll be several standing sets in each of TC2 and 3, with perhaps enough storage outside in the remaining dock area for the extra bits and set dressing?
In some ways ITV moving in has solved the set storage problem significantly. With two studios with standing-sets (and just a bit of re-setting between shows) the limitations of storage on-site for entire TC2 and TC3 sized set/strike sets has gone away for a couple of years.
It is possible ITV may try to squeeze other shows into TC2/3 in down time - but given that they will almost certainly want to run with fixed lighting plots for their ITV Daytime shows in there (rather than relighting between shows) , they may not have the re-light time for weekday stuff (unless it's very basic and just a simple re-dress of the same set with people sitting in the same places), and lighting three shows in one space with permanent lighting set-ups, could be tricky (you'll never get the lights you want in the right place for all three).
If I were a betting man I'd expect ITV Sport to use either Timeline's facilities in Stratford, or IMG's in Stockley Park. My money would be on Timeline as they have larger studio spaces.