Replace channels in main bouquet.

[DaMacFunkin]

Try this:
<custommix>
<inserts>
<insert target="143" source="109" provider="terrestrial_uk_freeview"></insert> <!-- Channel 4+1 HD -->
<insert target="195" source="110" provider="terrestrial_uk_freeview"></insert> <!-- 4seven HD -->
</inserts>
</custommix>

Tried that peterj, still says incomplete xml?

[Huevos]

/usr/lib/enigma2/python/Plugins/SystemPlugins/AutoBouquetsMaker/providers/

Goes in:
/usr/lib/enigma2/python/Plugins/SystemPlugins/AutoBouquetsMaker/custom

Reason you get the warning ([Providers] Incomplete XML cable_uk_virgin_CustomMix.xml) is because it is not a providers file.

From the README.txt:
The xml configuration files reside in /usr/lib/enigma2/python/Plugins/SystemPlugins/AutoBouquetsMaker/custom

[abu baniaz]

Works fine. I have shown the all chanenls as well as entertainment bouquet.

[DaMacFunkin]

Doh! Cheers for that working fine now the file is in the correct location.