Hi guys,
            I've been losing small amounts of coolant for months, I read the head gasket failure on the V6 was very rare so I kept looking for other causes, then suddenly the coolant bridge started to leak big time, I fixed this and the big leak stopped but the small one continued but got worse over a couple of week so I decided to look at the head gasket, which appeared in terrible condition, see photos, is this usual? What could have caused it and will the other gasket be in the same type of poor condition? 

I would suggest as you are this far remove the other head too, so that the pair are done. Do the exhaust manifold gaskets too.
Lack of anti freeze is the problem top and tail off it. Make sure 50/50 ratio is replaced.
Daz 

I would say you have done well mate, doing the other side now will be easier 
Think of this, at least once you have completed the job you know exactly what has been done to your car and will not happen again as long as you look after it. Also if it takes you two whole weeks, you have saved yourself over £500 per week compared to Vauxhalls prices. . 

Like you, on mine I took the nearside head off first as it is the slightly easier head to get off. It was the gasket on this side that had gone.

As I had bought a full gasket set with both head gaskets and head bolts, I decided to remove the offside head as well and was glad I did.

Although, the gasket hadn't gone it was in poor condition and I don't think it would have lasted much longer, so for the extra work involved, it was definitely worth it, rather than having to strip the engine down again in the future.

I also redid the oil cooler gasket, while it was apart as there was some blue antifreeze colour on the nearside head, replaced the thermostat, water pump, auxiliary belt and a new cambelt kit.

When I removed the oil cooler I could see the gasket had been leaking, I also had an overheating problem in traffic, which is why I replaced the thermostat, and although the water pump had only done 65k, there was a whistling sound when I revved the engine, the new water pump and auxiliary belt has cured this.

I hope this is of help

It looks like your missing a lump of the water jacket

Poor maintainance unfortunately, the coolant needs changing depending on the antifreeze thats being used

Good info Andy. 

Reckon this leak was to the outside world via corrosion of the block under the rear edge of the gasket?  Looks a bit like it to me.  May not be a doddle to fix if any significant amount of material has gone? 

Hope I'm wrong.

and some more, similar pics...

http://www.omegaowners.com/forum/YaBB.pl?num=1236287115