[RhysJR]

A whole load of new cast members was announced yesterday, headlined by the casting of Jason Manford as a new headteacher. Whether that is a spoiler or not is hard to be certain of, but if Angela Griffin leaves that will leave only one cast member of the original run still in it I believe. I don't really watch it (I've seen quite a bit of via my mum) but I think it has settled in well now.

www.bbc.co.uk 

Jason Manford to join cast of BBC’s Waterloo Road as new Headteacher Mr Savage
New series will also welcome new students to the school
  Source: www.bbc.co.uk

[UTVLifer]

Angela Griffin's character, Kim Campbell, was tipped to become CEO of the academy trust that Waterloo Road has just joined in the series 13 finale.

And judging by this line the press release, I don't think Angela is leaving (just yet) - While Manford's new role as headteacher will leave fans questioning how the future looks for current headteacher Kim Campbell (Angela Griffin), viewers will have to wait and see how the storyline plays out.

[TMD_24]

I think going by the press release that Angela Griffin will still direct some episodes as well so not totally gone from the show.