The episode you're referring to is:
The Bay (ITV / ITVX, 2019–) Season: 1 Episode: 3 Original Air Date: 3 April 2019 (UK) the bay s01e03 msv
Following the post-mortem results, DS Lisa Armstrong and the Morecambe Bay police team confirm that the victim (Dylan) died from a blow to the head, not drowning. The investigation turns toward the boat MSV Selkirk , a dredger where Dylan was last seen working. The episode you're referring to is: The Bay