Bicycle, needs attention (Moorlands LA1)

This mountain bike was built from upcycled parts by Pedal Power some years ago, I rode it, handed it on to my son-in-law, it's been in his shed some time, so there's some surface rust, the chain is rusty and gunked up, the tyres need inflating, possibly punctures repairing. But with a little work there's a usable 10 gear bike for someone to get about on.