Firstly, I looked for an unlock service and then chose Unlocks as their price is the lowest and the site was clear in simple steps and explanation. Followed instruction and sent my IMEI, my details, paid by card and around 4 hours later received my email with my unlock code and steps to unlock the phone via given link.
Applied the steps, entered code - unlocked, perfect. No longer Vodafone set, use my own preferred provider and sim.