My girlfriend wants to use giff gaff pay as you go sims, for herself and her daughter. My gf has a Nokia lumia 800 and daughter a iPhone 4s both are now out of contract. Question is will they need unlocking to use giff gaff sims? 

It depends where you bought the phone from. Usually when you buy it from the network directly it's locked. Places like CPW and P4U usually sells unlocked phones.
It depends where you bought the phone from. Usually when you buy it from the network directly it's locked. Places like CPW and P4U usually sells unlocked phones.