In running FSX and having mixed results adding aircraft.
They seem to install ok, but on some the aircraft model  textures just show a grey aircraft. Ive had a look in the files and all the ones seem to be there, Ive noticed this seems to be the add on with multiple liveries.  Is there something missing in these files are do i need to modify something manually . Advice appreciated. ;)

Welcome in here.
Maybe you should have posted this in Flight Simulator X.

If you're talking about paint addons you need to be sure its for the right ac. Then you need to add the repaint tex folder into the aircraft.cfg, otherwice it wont be readed.

Like this

[fltsim.0]
title=Tiger Moth VHDHA
sim=Ants Tiger Moth 00
model=
panel=
sound=
texture=VHDHA
kb_checklists=Ants Tiger Moth 00_check
kb_reference=Ants Tiger Moth 00_ref
atc_id=DHA
atc_id_color=
ui_manufacturer="De Havilland"
ui_type="DH82 Tiger Moth"
ui_variation="Yellow VH-DHA"
ui_typerole="Single Engine Prop"
ui_createdby="Ant's Airplanes"
description=The De Havilland Tiger Moth is one of the most famous aircraft ever built. Originally introduced in 1932 as a basic trainer aircraft for the RAF.Such was it's popularity that nearly 9000 were built and even today around 500 still fly. This aircraft represents a modern Tiger Moth as it may be flown today. It includes a few of the comforts of modern life you may find in such a plane like a radio and a GPS. It is also fitted with a tailwheel rather than the skid you would find on originals.

[fltsim.1]
title=Tiger Moth VHWFW
sim=Ants Tiger Moth 00
model=
panel=
sound=
texture=VHWFW
kb_checklists=Ants Tiger Moth 00_check
kb_reference=Ants Tiger Moth 00_ref
atc_id=WFW
atc_id_color=
ui_manufacturer="De Havilland"
ui_type="DH82 Tiger Moth"
ui_variation="Camo VH-WFW"
ui_typerole="Single Engine Prop"
ui_createdby="Ant's Airplanes"
description=The De Havilland Tiger Moth is one of the most famous aircraft ever built. Originally introduced in 1932 as a basic trainer aircraft for the RAF.Such was it's popularity that nearly 9000 were built and even today around 500 still fly. This aircraft represents a modern Tiger Moth as it may be flown today. It includes a few of the comforts of modern life you may find in such a plane like a radio and a GPS. It is also fitted with a tailwheel rather than the skid you would find on originals.

[fltsim.2]

Try it with DX10 preview turned off