Off flavours in my first three kit brews. Help!

[Agentgonzo]

metabisulphite (campden) solution? Is that literally just a campden tablet in hot water dissolved to do a final rinse?

Yes

 

[Sandimas]

The problem with these things is that you can end up chasing your tail e.g. a previous poster blamed VWP, yet lots of homebrewers use it and it's sold in most homebrew shops: I've used it for 12 years and never had a problem, provided it's rinsed well. And if you want to eliminate chlorinated water from the equation, just buy some cheap bottled water from a supermarket for your next brew.

Persoanlly, I think it's something more fundamental and simple: temperature or infection.