Had the very same problem with my cabby, sorry to say but new injectors were needed, no cheap at £30+vat each. new filler neck again has to be the most expensive about £100(different to mk1 tintops)
Drain the tank through the lift pump hole under the back seats, clean the metering head and fuel lines with an airline(blow air through all of the fuel ways), clean the main pump and the lift pump thoroughly. This did the trick for my car.
hope this helps
ps. you can not clean the injectors(after they have had water through them), anyway the should be replaced at about 80k.