two large center pains and two side opening windows. they open from the side so i cannot swivel them round to cleanHmm, a bit of a poser there, jokay.
Try and get a hold of the maintenance dept at the council, or the manufacturers of the units, to ask if there's a catch within the frame which you can trip to enable the side panels to swivel more, allowing you to get your hand out through the hinge-side gap. I'm sure the council would have looked at the possibility of tenants cleaning their own windows from inside. Are there higher flats than yours with the same design windows? How about asking your local counsellor, they've usually got contacts in the right places, and they'd be horrified to be told that windows they had fitted weren't fit for the purpose, as you should be expected to be able to have them cleaned, surely?
Have you asked some neighbours at your height, or higher, how they clean their windows? Does any of them know a friendly fireman?
Is there a resident's committee who could recommend a solution - this must have been asked before.
I've searched on Express Cleaning Supplies but can't find any backflips or vice-a-versas there, so check out . . .
http://www.windowcleaningwarehouse.co.uk/index.html and click on "dual purpose" on the top blue bar for a device which should help you. You'll probably need to get a short extension pole too, so click on "poles" just to the left of "dual purpose". Then again, you'll probably get away with using a short piece of dowelling, or a cut-down piece of broom handle - because you don't want to bump into the open hinged window just behind your elbow. Make sure the backflip / vice-a-versa is VERY secure on the end of the pole - just in case, you might want to get a piece of cord and tie it to both handle and pole, the name of this device escapes me at present, but it's on the same idea as a kid's lead which fastens on it's wrist with the parent having the other end, but shorter - if you know what I mean!
That's as much as I can advise jokay, so best of luck and all the best. Just think, if you make a success of yours, you could have a good little earner there - how many flats are there?