Ok
Wheels:
The 12" Silent runner is a popular one and that can screw to the bars easily so you don't have to worry about something to stand it on. The cage mounting plates are separate though and about another £5.
www.tomspetcreations.com
Cage attachment brackets
www.tomspetcreations.com
There are other 12" wheels as well that others may have recommendations for.
Gnawing material
Whimzees toothbrush chews, sprays, Chew sticks (Whimzees can be got from a pet shop individually or from Hopes Healthy treats below)
Rosewood do various flavours of these
Vitakraft do various flavours of these
Bedding
I use Fitch. Kaytee Clean and Cosy is popular on here. Both are fine for holding tunnels. Carefresh seems less popular these days - it can be a bit dusty.
Wood chews
Apple wood sticks, forage sprays and lots more items on this page
Browse our wide range of Hamster sprays, forages, treats, toys, tunnels, enrichment and much more! Promoting only the best care for your small pets!
hopeshealthytreats.com
Cardboard
Toilet roll inners, tissue boxes, shoe boxes, amazon boxes are all fine.
House/main hiding place - lots of info here
How to choose the best house or nesting box for your Hamster. The best houses have multiple rooms for nesting, hoarding and for a litter tray. This mimics a Hamster's burrow and they can have normal behaviours and enjoy a dark, safe and cosy...
www.thehamsterforum.com
Food and water
As Elusive mentioned above, Harry Hamster is fine. It contains everything needed and the correct protein levels and is sugar free. If at some point you want to look at something with more variety, there are other options, but most of them ship from Germany.
Water bowls I'll leave others to recommend. I use water bottles and like this one - it doesn't drip and lets water out easily and comes with a clip to attach to the bars, so it's easy to take the water bottle in and out.
Sand
Also listed on the Hopes Healthy treats page. I think Rainbow uses that one (Natural sand). There are various others and people have their preferences. Others may have other suggestions. I see the Natural sand is out of stock at Hopes Healthy treats but it's available on Amazon