How would i fix my venetian blinds?

hi, try and imagine this... i live in an old school, that's been converted into flats, my flat has a large sash window which stretches right up through the ceiling in my living room up into my bedroom to the windowsill, which is just over a meter high from the bedroom floor, and covering the gap is a single large pane o glass which if you are sitting on the windowsill in the living room you can knock on the glass. the other day as i was opening the blinds they fell of the fixings. the only way i can think of to put them back up is to get 2 tall people to stand on the living room windowsill, in-between the 2 panes of glass and try place them back on there fittings but this can be pretty dangerous as im on the 2nd floor in the building and only have single glazing. there must be another way, how would they have got them up in the first place as they definitely didn't come with the property when it was converted. please help me! xx