Hi Maggie. I'm not familiar with those baskets but if I have a failure around the outside of mine I just scrape it out and and shove another in the hole. They always seem quite okay with a bit of shoving and pushing...x
I've had some begonias rot this year Maggie (although it didn't help that Mr BM put the irrigation system on ALL bloody night). I'd agree with gness. Poking and proding is the way forwards.