Permanent residency

Not compulsory to do, but the new TIE’s have an expiry date, so after 5 years as temporary, when you renew, you’ll automatically get a Permanent residents card, which will be valid for 10 years.

Thanks. I have the green card but understand I don't have to change it as things stand. 

As yet, no - although government have “advised” that it is beneficial.  I do note quite a few residents with green cards have been turned away from airports in UK and in Spain, due to a misunderstanding of requirements.  A benefit of the TIE is as it’s a biometric plastic card, there is no requirement to carry your passport as proof if ID, as the TIE is ID - plus it’s more durable.

Thanks Dario.