Gaz,
I use stainless steel guitar string with good success. Inexpensive and easy to trim to length with a good pair of "nippers" it works like a charm, the only challenge is to drill out the often tiny struts to receive the "pin". Get the finer ones, labelled PL 011 or PL012, they are 0.28 or 0.30 mm in diameter and should be available in 20 to 30 inch lengths for a dollar or two each, one will easily supply stock for half a dozen projects. I insert them into a bit of medium CA and they are permanent.
Any music store should have them, hope this helps with your question.
Cheers,
Lance