Not all the landline numbers start with 01, all the big cities and urban areas got moved into 02 to make space decades ago when there was concern we might run out of space.

Also, 03 is guaranteed to cost the same as 02 but has no specific geographic link, so it's often used for helplines, customer service, that sort of thing, and for people who want to have a landline (or multiple landlines) but do not want to reveal their location.

04, 05 and 06 are part of that roped off space we reserved in expectation of a need that's now unlikely to ever materialise, oh well. In the era when it was conceived people thought "Internet shopping" was a ludicrous idea and still imagined "Video calls" would be a thing you'd do as a telephone call somewhow - so what did they know.

07 as you said is where non-geographic mobiles live, as well as some other services at similar price points

08 is "free" or sometimes revenue sharing prefixes and the 09 prefix is where "premium" services live, you know "Chat live now to singles in your area".