There's massive demand for tutors, especially 11+ tutors, which you could potentially do with your English degree.
If friends wife doesn't is a teaching assistant, however for extra money she helps child with English and reading. Advertised via gumtree, and charges £10 p/h group session (max 3 children), and £15 p/h 1-2-1.
With the 11+, the child needs a to cover 4 areas in the exam, 2 of which are verbal and comprehension. You would get less interest with just covering these 2 areas, but there is demand.
We were paying £20 p/h for out DS for a 2 hour group session covering English and comprehension. The person was recommended, very experienced and confident. We left soon after because there were 13 children in the class, and I felt that the classes should be smaller. But she was making £520 from the 2 hour sessions.
As your just starting out you would obviously have to charge less, and possibly could even offer a free starter lesson. Most lessons have moved online, but.you could use zoom or google hangouts. It would require preparation on your behalf before lesson, and you would have to provide a quite atmosphere.
Do let.me know if you require further information.