Thanks again for all the replies!
The tank is set up now! I'm just waiting for the filter.
I'm gonna order the ammonia online. I'm still doing my fish-in cycle on my smaller tank. It's been over a week now since I got the filter set up and I still have no nitrites. It's going to be a long time I think.
As for dechlorinator, when doing a fishless cycle, apparently it's best to use one that doesn't break up ammonia or add any beneficial bacteria to the water? Am I right with that?
Can anyone suggest a good/cheap product that does this? My last bottle cost me £4 for 100ml.
It's lasted about a week. If I were to use this one in my new tank, it'd take 2 bottles of the stuff. (425 litre tank!

).
I'm sure I can get a bigger bottle for much cheaper?
'Tapsafe' seems to be a good, cheap bottle. I think it was about £8 for 500ml? But it adds beneficial bacteria to the water.
If anyone knows which one I need and where the cheapest place online is to order. That'd be great
Thanks again!
Chris.