Hi Treetop.
I've moved your post to the Nest Box forum, as that is a better place for your question. I believe that our tits only raise one brood, as they time the hatching for the emergence of caterpillars.
Now I'll wait for someone to tell us that they've seen more than one clutch successfully raised in a year!
In other words... never say never LOL.
I've also subscribed you to this thread so you can keep track of it.