Where have my Birds gone

Your birds would have valued the hedge as a secure place to flee to when they spotted a sparrowhawk or cat or even yourself, Sheil, in their vicinity. Assuming a 'normal' sized garden then some large shrubs, including evergreens, growing through it would help.

Its so true they feel less vulnerable when they have not such a far distance which to fly so as to be out of danger, from sparrowhawk cat etc, with a good hedge that has some depth to it (and not to far from feeders) and which will make access difficult for cats (birds of pray are not about to fly into a hedge after a small bird) will be ideal :-) plus they need a good warm tree/shrub/hedge to keep warm in winter.
Thick hedges with wide bases that provide plenty of cover are very good.

i think you will soon have your birds back. :-)

Do the birds have other plants or structures to perch on in your garden Sheil15? Even tall garden canes can be helpful. I find most of the birds visiting my garden (even ground feeders) approach the feeders from height once they know the coast is clear.
Don't be put off offering food once they are comfortable again they will return.

Thank you all for your advice I now have a six foot fence down one side and a garage and fence the other side of my small garden at the back I have a large pergola, on which I have planted two types of Wisteria, but they are only small at the moment I have put shrubs in also but having only lived here for two years they are all quite young but I will put in a few climbers on the fence ie: Honey Suckle for the blackbirds. thankyou again I will keep feeding them all and hope for the best bye for now Sheil15 x