1983 Sovereign - problems while cold.

Hello, I've just recently bought an '83 Daimler Sovereign, with an unbelievable 32K on the clock (MOT's do point to this being real though - as does the car's condition). I am, however, experiencing some irritation: When started from cold, for the first 10 minutes or so - until the engine is warm, the car seems to lack "go", at between about 1800 and 2200 RPM it will splutter and sound generally rough. On one occasion, when I looked under the hood at this time, there seemed to be fuel leaking from what looked like the cold star injector. Once the engine is warm, the car behaves impeccably - and I can see no evidence of fuel leakage. Is this likely to be a cold-start injector problem - or is there something else I should be looking at? Any help would be much appreciated. Thanks, Andy