Hi, thanks for the replies and feedback, I have re fitted the faulty SE screens in 5s phones and they have worked fine, so it was 100% the screens fault. I contacted my supplier and the said they should work, they contacted their supplier and was told there was a mistake and send a new batch out. The new batches have been working fine ever since, however the 2 SE phones that had the fuzzy screen problem never worked again so it must damage something on the board. So, SE compatible screens DO work but be careful, if it goes fuzzy, remove straight away to avoid damage!
I have contacted the supplier and they said their supplier said that the 5s screens are not compatible SE! I'm guessing it must be a new revision so may be worth checking before installing to avoid no displays on iphone SE.
If you have another computer, you could try running a surface scan on the hard drive, for example if you have a seagate harddrive, you can run sea tools and check for bad sectors, if it finds any it usually gives an option to repair, sea tools can also check other brands but doesn't fix the bad sectors on them. If your drive has bad sectors I would recommend backing up and replacing as soon as possible.