As said, Church Bank is a good spot. I never lose any gear there, nice clean ground apart from the tyres close in. I've always caught more fish at the spot you have already fished at the far end of the marina. I usually fish off the bit with the boards and don't lose much gear if I hit the middle of the river.
Near the police launch in Jarrow is not a bad spot either, but you do need a rod stand as you are fishing from the river bank.
Hope this is a help.