Many many thanks again for the great replies folks, I"ll try and answer the questions you posed in the best way I can.
I figured a 2/3 size of the pot would take the pot down right there which was what I was wanting to do, the pot was big enough and although I had top pair I cant give anyone the right odds to call with a draw and after playing online for long enough I know how easy it can be to get sucked out on and the bet was purely designed to finish it right there. If I had bet less I would have looked weak and if I had then been re-raised I wouldn"t really have known where I was. This was a big buyin for me so maybe I just over-estimated the level I was playing against and perhaps this also contributed to the fold. With 2 guys pushing allin after checking my top pair just didn"t look as strong anymore. The bet therefore also gave me, although negligible I agree, some wiggle room to get out of the hand and take my chance later on with an allin move to try and double back up again.
The QQ on turn and river although giving me the full house was actually not needed anyway because if I could have seen the others players cards I am pushing allin with my AQ after the flop.
If I had missed the flop and the other 2 players had both checked to me I would probably have bet the same amount and tried to take the pot down. I dont see the need to push allin here as the 900 bet should surely do the trick the same way as an allin bet would have, I think anyway.
Remember we were only an hour into the tournament and 3* was taking down most pots uncontested at this point as the table was playing very, very tight, hence the fold after the 2 allins.
To conclude the story , I was left in a bad position with only 1700 chips left and somewhere in the region of 500 players remaining but I did manage to double back up about 10 mins later and then played some good stuff to go from almost last in the tourney to top 20 within an hour and I eventually, after a further 4 hours of play, went out in 65th place and won myself 750 euro which pleased the wife no end
I went out when my ac tc lost to ks
in a sb bb confrontation.
Incidentally the AQ in question proved to be the 2nd best hand I had all night, only bettered by picking up QQ which resulted in picking up solely the blinds.
I hope this has been readable for you all and I await more comments if possible.