If you want to render the brickwork, it really ought to be wired first (galvanised expanded metal lath fixed to the brickwork). It's because render often doesn't "stick" properly to face brickwork. If you're in a rough weather area, that makes it more important.
I'm only talking about regular sand & cement render, I don't know about K-Rend.
If the brickwork has become really tatty, consider painting the brick direct. A good Weathershield, or Farrow & Ball colour can look really good.
Treat the timber bits (assuming they're not painted, with something like "Sadolin"