Move the filter to the other side of the tank if you can, it should clear that side up. Leave it on. Always leave your filter on, or your tank can't cycle right. That test kit doesn't sound like its a very good test kit. There is a much easier way to test your water. Take your water in to get it tested at the pet store. They may do it for free, or they may charge a little for it, but it will be worth it, because they can teach you properly how to do it. I just have my local pet store do it, as it is easiest this way while I get my shoping done.
Always keep your filter on, never turn it off even when there is nothing it it if you are planing to put something in it. Cycling is very important. Also, having live plants in the tank helps get rid of Nitrates. They act as Fertilizers for the plants, but Axies tend to root up plants, so plants that float at the surfice like hornwart or duckweed are good. Temp needs to be very low. About 17 degrees Celcious. The higher the temp, the Axolotls will stress, and get sick. Their metabolism speeds up. Since you live in merry old England, I would think it doesn't get very warm there. is it cool there often? If it is not, you can try frozen water bottles to keep the tank cool, or invest in a cooling system for aquariums. They run expensive. My filter isn't very good either. I am investing in one in the link.
http://www.bigalsonline.com/catalog/product.xml?product_id=22033;category_id=1711;pcid1=2885;pcid2=
Canister filters are very good as many people on this forum use them, and recomend them to me. If you can find a store near you that has Canister filters, shop around, get prices. Rena is a good brand. People here on this forum can help you pick out the right filter. Also, it is very important to have a turkey baster to clean out waste that the Axolotls leave behind. Clean it out right away, and any uneaten food. do you have a gravel vacuum? Like a Syphon? It is important to have one of these too. only vacuum the top layer of the sand, just lightly or the sand will get sucked out.
Here is a link to why I am upset.
http://www.frognirvana.com/images/products/bestfreinds-th.jpg
the two cats depicted in the sculpture have such a remarkible appearance to my two cats. I have a Siamese long hair, and a white and orange cat. The Latter is 15 years old and I worry every day when he will pass. I love him so very much. The Siamese Long hair is a year old, a bit older than that. The two of them love each other to bits. When I came across the sculpture, it made me cry! It is such a sweet sculpture. I hope my husband will surprise me with it
but at the same time, it broke my heart to see it.