I can tell you where to find a cheaper bike stand for less than £25. If your Aldi has that many they will have to cut the price to shift them. They take up a lot of floor space so you may not have to wait that long. Incidentally, I saw a similar stand in Halfords yesterday but that was advertised at £50.
I used mine for the first time yesterday and I have to say that balance didn't seem to be a huge problem. I used the clamp on the crossbar and moved a few inches along and it seemed secure at both points. I had the stand on grass which was neither level nor a firm service but the legs are widely splayed which must help.
The biggest problem was lifting the bike up to the clamp which was anything but easy going. If you are not physically strong you will have a problem lifting a heavy bike on your own to a height where you can stand up to work on it. I then found it easier to lift the front wheel off (hub motor on the front) with the bike upside down so I took the bike off the stand altogether for the rest of the inner tube changing procedure. This means I can't be certain whether the bike would still have been stable on the stand without the front wheel on.
When I bought it the bike was supposed to have Kevlar tyres but I can't imagine a small thorn would have got through had this really been the case!