I bought the Metro Metal Bed Base - King Single. It went together well, the instructions were clear. There was one error, the screws in step 7 were marked "S" but they should be "M" the same as in step 11 (they go through the same piece of steel). There's heaps of room under the bed, 310mm by my measure. The design of the slats is different than that shown on the product page, the ends are pressed closed and the slots in the rails are thinner and also the two halves are hinged together with a pin rather than having an extra joining piece. Functionally it makes no difference though. Seems sturdy enough and doesn't rattle. It has clearly been made to a budget but it seems well designed and good value.
I bought the base in November 2025, it's now 6 months later and I haven't had any problems with it.
I will say, when I bought it, it was on special for $109 including shipping. I see the current not-on-special price is $299. A quick search shows there are other similar options for cheaper at the moment, so it pays to do your research.