Unlock old phone

[#1]

I have an old Motorola G5 which I no longer use. I got it a number of years ago on the PlusNET network. I'm still a PlusNET customer, just don't use this particular phone any more.

My mum was planning to get a SIM only deal with Virgin, and I hoped I could give her my old phone. However it seems the Motorola is locked.

How do I go about unlocking it for my mum to use ?

Thanks

[#2]

@Renegade_Pirate 

I’m not aware that Plusnet lock phones.

Is it possible that the phone was originally used on the EE network? If so it would have worked on the Plusnet network.

[#3]

Have a look at that unlock service link I sent you. They are very reliable and I've used them several times.