I am after a Red Dot with a picatinny mount. I would prefer one of the none tube i.e. open types with a flat piece of glass but am open to offers. I don't want to pay a huge amount but want something that is quality and would pay a bit more for a quality one (say up to £150 tops). Something like a Doctor or a used Shield would be ideal. I have an OK Doctor type copy that works OK so another one of those would work. One with multiple reticules or a circle/dot would be good. Thanks.