TD5 ticks over until throttle is pressed.

Hey, New to the forum, looking for advice.

I have a 110 Defender TD5, 02 plate.

When turning the ignition on and try to fire up it ticks over, coughs and splutters until I press the throttle it fires up.

Doesn't matter how long you wait. Whether I press the throttle straight way or a few seconds waiting. It doesn't fire up until the throttle is fully pressed.

My best guess is fuel pump although it has already been replaced a year ago.

Any help would be greatly appreciated!

Hello and welcome
Best to ask over in the Defender section of the forum https://www.landyzone.co.uk/forum/defender-90-110-130.7/