Can you suggest of cash in hand jobs I can get at London, UK?

like in "irina palm" movie?

You could offer to walk people's dogs for them, babysitting or wash cars.

Since you are on the computer, get a scanner with about 600DPI resolution.
Find people with money who have family photos that need to be digitized to be preserved. negotiate a price with them for digitizing the photos and put them on CD ROM. Photos hanging on walls is a good example,
There is available archival quality CD ROM disks. These CDs have special films that will last a long time.
Visit doctors and lawyers who have old papers that may need to be preserved.
There is a vast amount of information which was created before the computer revolution which will be lost if not preserved. There is a market for doing this.