I had an interview and got an offer in late october (took about 4 weeks to come through track.) Halfway through the waiting i got the 'we're looking at your application and here's some things you might be interested in' letter. I knew i had an offer though cos i was told at interview.
If you have one good luck, and tbh its probably one of the most casual interviews you'll have. They also said they only interview those who they are considering for offers.
As for the 'bring an object from home,' i just took photos and project work of my GCSE resistant materials work. Was never asked about it though so theres not really any need to stress.