FUEL FILTER HOUSING CONNECTIONS - WHATS RIGHT?

I am thinking my TD5 poor starting issues may be down to the air vent valve in the fuel filter housing, having read other threads I thought it's best to replace the whole housing with new fittings included. But I am getting confused by different comments on this site and other sites as to what goes where in the housing itself?
The picture below shows the new housing, I have marked the connections 1 to 4, 1&2 are the connections closest to the chassis. Connection 3 has the air bleed valve in it, connection 2 has the ‘duck bill’ non-return valve in it – the other two connections are plain tube.

Can anyone confirm these are the right positions for the air bleed valve and non-return valve?

Thanks for help

In reality it's a whole mess with the non-return valve's position cos on some defenders and late discovery facelifts it's in port nr 2 as in your pic but according to the workshop manual it should be in port 1 and it is there in some cases, Eu2(pre-facelift) D2s like mine too ddidnt have that valve at all from factory and no problems, the air bleed valve is important to be in faultless, see this TD5 Fuel Pressure problem

Seems that I'm having problems with uploading at the moment!
But I hope this may help! Taken from another site!

https://www.defender2.net/forum/post524704.html

Seems the site isnt allowing anyone to upload images..... Probably a cost/bandwidth issue with the site owner....

Another issue I found with the positions of the outlets is whether its left or right hand drive.....

Thanks for the responses!

Why not just refit the same as it is now, or am I missing something ?