Haworthia or aloe?

Please may someone tell me what plant this is? I bought it as a tiny unnamed succulent about 8cm diameter on the clearance shelf at a garden centre. It’s been repotted 3 times and thrives on a west facing windowsill. I’ve always assumed it’s a Haworthia but my searches say they don’t get that big and this thing is now 25cm across and 20cm high and producing babies! Until yesterday, it had a rather creepy looking stem about 30cm long with an insignificant white flower.
it has a rough texture with slightly serrated teeth along the edges of the leaves. The white speckles are more pronounced than the photo shows too.