I'm a bit confused by this why does Jay have a tag for 3 months while Ben was arrested for a few days and now is scott free ? that makes no sense to me .

Jay admitted it and kept Ben's name out of it as far as the mugging happened

plus his fingerprints were all over Lucys phone

correct and Ben would have a plausible explanation "she's my niece, she was showing me family photo's" no such reason for Jay

Jay was sentenced for the robbery of the off license nothing to do with Lucy's mugging, as far as I know the police still know nothing of the mugging

I still think it's a bit out of character for Jay to rob an off-license in the first place. He hadn't really done anything illegal before then had he?

He started off as a bit of a tearaway and did a bit of thieving as a kid

It was Ben, jay was just there iirc

Erm yes! He covered for Heather's murder!!!

Well Jay still knew Lucy, and is Ben's best friend who he lives and works with, so would probably have encountered her just as often as Ben did... No reason on earth why Lucy might not show him photos on her phone.

I think Jay doing a runner also didn't help his case either. Jay needs to stop getting involved with Ben. You would think he would of learned after covering up Heather's murder. Jay showed so much remorse and hurt for doing that, It felt like a massive back step for the character to have been involved with robbing an off license and hiding evidence linked to a murder case.