Strangely, Mel doesn't annoy me as much as she sometimes did in her first stint. Maybe because they're writing her as more of a hard character this time around, which plays more to Tamzin and the character's strengths.
I will also say, Yorke seems to have given Kat back her sense of humour - that was a vital part of the character and was missing in the last stint (especially all the misery DTC reaped on the character). The Slater set-up is a bit ridiculous, and I wonder why Yorke even bothered with bringing Jean and Big Mo back. He hasn't given Kat anything substantial to do yet either, but I sense he's taking his time to re-establish her somehow and hopefully move her forward from her last stint - she is his definitive character after all.