I guess that could be the problem.
Can you try flashing the lastest firmware from here: https://cyanogenupdatetracker.com/downloads/
It should be Cyanogen 13 (Android 6). You can use TWRP for that.
Afterwards flash the lineage zip.
Thanks - it worked! I now have a working OS, I am so pleased.
I do still have a problem not sure if you could help as not entirely sure what has caused it.
Although I can receive and make calls and send texts I am not receiving texts (SMS) on my SIM 1 (giffgaff). Other sim seems to be working (And I could send a text from one sim to the other on the phone)
I've tried every thing I can find online (manual roaming etc) Put the Sim in a different phone and after a while I got 4 texts from one sender, but no others (have family sending me test sms).
I restored texts an old backup on google drive, there were thousands. I have tried to delete some in messenger but they don't seem to be being deleted. Currently backing them up to email. I'll then try and clear the data in messenger. Is it possible to reinstall just the messenger?
Also my google email (even after installing gmail) is showing as I have an empty inbox - (says 'you've finished - nothing in inbox' with a cartoon of someone relaxing, reading a book....) if only that was really the case .
Thanks again ...at least I now have hope of getting back a fully working phone and it is a lot faster than it was....