Hi Natasha, welcome to fishkeeping
I'm glad to hear you have decided to do a fishless cycle. Yes, it can get a bit boring looking at an empty tank, especially if friends start making comments, but it easier and less stressful for both the fish and us
I've googled the tank you mention, but just to check, is it
the bow front or
the rectangular one ?
The reason I ask is because the rectangular one is longer than the bow front which will affect which fish are suitable for each one. Some fish are pootlers others are dashers, and the dashers need a bigger tank than you'd think from the size of them.
With your water conditions and tank size, you need to look at those fish that like hard water and grow no more than 4 or 5cm long.
The various sites I've looked at say the tank comes with a PowerBio filter. It would appear to have 2 different types of media, just sponge or sponge with carbon. When you get the tank, can I suggest you look which media it comes with as the just-sponge type is better than sponge-with-carbon. (Media means whatever is inside the filter)
The info from your water company:
Your pH is slightly alkaline at 7.5
You have hard water. When you are researching fish, some websites will give the prefered hardness as ppm (in your case your water is 283) and some give it as german degrees (yours is 17)
Alkalinity - you want the second one, 206. This is a measure of how much the water will resist a change in pH. Yours is high, so it will be hard for you to change the pH. Don't bother trying
You'll read about something called KH. This is virtually the same as alkalinity. Having a high KH/alkalinity means your pH should remain stable during the cycle.
Nitrate - at 21, it is middling. The UK allows up to 50ppm in drinking water, and some people do have that much. The importance of knowing your nitrate is because the higher it is in the water supply, the higher it will be in your tank, and there are some fish that need very low nitrate.
I think I've thrown enough info at you for one post
Jesnon lives near you and she'll be able to point you in the direction of good fish shops when the time comes to go fish shopping