Hi!
I had an interview for Bedfordshire uni last year - you literally can take absolutely anything, i took bongo drums as i thought they were quite versatile. No you don't present as if your teaching a class, you just do a 5-10 minute presentation on how you could use it to benefit learning! Try to choose something versatile that you can adapt and use for different areas of the curriculum which also suits different methods of learning - hands on, written, creative, physical as the more you have to talk about the better you can get your ideas across. I found it helped me to do a mind map of the different areas of the curriculum the artefact can be used for and then went on to develop how it can be used. Just read over it alot so you remember what you have to say but if you forget things dont worry! I completely froze up in my presentation but still got offered a place! Message me if you want any further help - in the meantime, Good Luck!x