I think I know the series you mean but at present I can't remember what it was called. If I remember I'll come back to you unless someone gets it in the meantime.

Is it Fringe?.....Sky One

Nope.

Not a scooby then

I've remembered the series I'm thinking of.

Poltergeist: The Legacy. I don't think Channel 5 showed all 4 series made but they definitely showed at least 1 series. IMDB link

The lead actor was Derek de Lint:

THAT's IT!!

Well done El Loro. Your fountain of knowledge scares me sometimes. 

Thanks anyway 

I scare myself sometimes particularly when I look in a mirror . I couldn't think of the name of the series or the name of the lead actor but you mentioned him being French and that made me realise that he had a "de" in his name, then I did a name search on IMDB using that and and after a couple of pages, I saw Derek de Lint and knew that was who I was looking for. So it comes down to searching rather than an encyclopedic knowledge.

I'm just watching an episode on Youtube... my god the acting is awful