Pattr in bpatcher picking up value from parent on load

Hi,

I'm sorry to add another topic to the already extensive list on the subject of pattr issues, but I'm stuck and couldn't find a solution on the forums despite extensive reading!

I'm trying to get a bpatcher to pick up the value of a pattr in the main patch on load (in my case a file path required for preset handling) but I'm having trouble. I can successfully bind the pattr in the bpatcher to the pattr in the parent, but on load it outputs a '0' rather than the bound value.

I'm sure this is a simple problem but I'm getting nowhere with this and wondered if somebody could point me in the right direction?

I'm attaching a zip file with two .maxpat files: unzip and open bpt_top.maxpat then follow the comments to recreate the problem.

Thanks in advance for any help

Tom