Can anyone recommend an el cheapo mains-powered drill from one of the
sheds. Suitable for light home DIY use, just wood drilling and the
occasional wall plug into breezeblock.

Any non-SDS mains hammer power drill will suffice for those tasks.

Additional features you may find useful for other tasks:
1. Reverse
2. Twin speed (gears)
3. Variable speed (touch sensitive control)
4. Torque control
5. Rotor brake (stops instantly you let go of trigger)

Christian.