If I remember rightly didn't RWB have similar blood results to Sheila ?
He didn't have similar blood. He had identical blood. They were both A, PGM 1+, EAP BA, AK-1, HP 2-1.
But regardless of that he is not my prime suspect. Allbeit he remains a possible one.
Its not plausible to me that he would know his blood would show up the same as Sheila's across five different areas of testing. But even then he does not have to, you could argue he was ignorant and took the risk. You can never really rule him out 100%