Croozer bike trailer - needs some work (Cutteslowe OX2)

This has been out of action for a while, but only needs a few nuts and bolts to get it back. In particular two of the fixing bolts for the cross bars are missing - see photo - one has been replaced but the other needs a bolt. Pretty standard, I think. The tyres are flat, so may need new inner tubes. I am not sure how it fixes to the bike. I have an attachment but can't see how it works. The wheels and the towbar are removable for storage and the towbar can be raised to use as a hand-towed trailer. It needs a clean up but is otherwise ok. The base has a section which has separated slightly from the frame - see photo. I'm not sure how much it matters.
Dimensions - width 33" length excluding towbar (removable) 30" height in use 21", packs down to 33" x 30" x 6" approx. Towbar lenth 30" approx. Wheels come off, sides fold down, towbar removes.