escort diesel doesn't start?

Got a 1.8 diesel turbo escort ...it suffered from poor starting inthe cold ....so I changed the glow plugs..this helped...then a week later I decided to change all the filters Air, oil and fuel...and now, it doesn't start ...any ideas? checked all the fuses...checked the glow plugs..all ok..stuck 5 ltrs of fuel in it ..the battery is fully charged and turns the engine...