0:09 the scene on the beach where the second inspector goes to examine the body, on the right corner of the screen, you see the mother in the red dress enter running towards the group of onlookers on the beach. . Next scene she's still on the boardwalk running to the beach.
The boy who was killed was 11 years old and had a paper round. You have to be 13 years old to work (even part-time) in the UK.
When Olly tweets from the beach, his twitter app shows he is composing a reply to the account @broadchurchecho Subsequent shots show the tweet coming from the @broadchurchecho account itself.
When Beth and Ellie visit the beach, Ellie's cross-body bag strap is visible across her back, but all takes from the front show nothing across her body.