Try growing lettuce in pots - although I've got plenty of space for vegetables, I found that I could get decent sized lettuce from a 10 -12 cm pot, and also grew cut & come again lettuce, red & green leaf in larger pots, about 30cm. The reason I did this was that they keep cleaner, we tend to eat more if they're close to the house and they dont get attacked by slugs. I shouldn't think the root aphid would get to them if you use clean compost.
The other crop I had more success with in containers (seed trays in this case) was radish, really I think because they need to grow quickly and like a lot of water, and I can't give the ones on the allotment as much as they need. This was a tip from Georgie, who grows everything in pots!