Ahh ... first post ... welcome to FSM Stuart72. Good to have you join us.
When I build my recovery vehicle I used heavy upholstery thread. You should be able to find it at any shop that recovers furniture. I comes in many colours and I went with black which makes things easier. To prevent it from unraveling, just pull it across a candle, the wax will keep it nice and tight.
Here's a pic of mine.
Happy Modelling and God Bless
Robert