Best way to secure beading

[5oysterman2]

I removed a bit of beading to replace it. Behind it i found it stuck on top of broken bits of ceramic tiles with copious amounts of caulk. The gap behind it is 20mm deep in places, what's the best option to reattach it?

Would expanding foam do the job or should it be best reduce the gap it's going to fit with mortar & then glue it in place. Cheers

 

[foxhole]

Just blobs of Fixall to back and infill tile edge with same at intervals, or grout.