Many thanks for your speedy response.
We have noticed the starring and raised hair as signals before aggressive behaviour particularly in one dog - when this happens we try to divert his attention with play to diffuse the situation.
I have in the past read up on dominant male signals, however at different times each dog displays these, such as the placing their head over the top of the other dogs, and they have also both displayed submissive behaviour - such as rolling onto their back in front of the other dog - so it has been very difficult to establish which one is going to be / is the dominant dog! But I will read through the links you have provided and now they are that bit older we may be able to identify which is alpha male.
We also keep an eye on play fighting as you say it can escalate but since they were neutered they tend to check themselves at teeth barring stage. Today's episode was completely out of the blue - they had just come back from a walk and no food or jealousy over attention was involved!
Within minutes of me separating them they are fine with each other and in fact seem to comfort each other, it seems to come as much of a shock to them as it does to us!
It is interesting what you said about Cocker Spaniels as we always assumed this trait came from the XXXXX XXXXX side!
I am just relieved that you did not come back saying that one should be rehomed as that would break my heart and I think if you had then i would have to of rehomed them both as i would not be able to choose.
We are very committed to both our dogs, (by the way their names are XXXXX XXXXX Lewis - I am a bit of a Colin Dexter fan), which I am sure you can tell from my messages, and we are willing to work as hard as necessary to ensure they are both happy and have a fulfilling life.
I will book them in with the Vets for a check up - they are a couple of weeks off one year old now anyway so they will be going in soon for their booster injections.
When you say the dogs should be on a leash - can I assume you mean just during the two training sessions?
Assuming we follow all your directions, which we will, how long would you anticipate it taking before we see a difference, (also bearing in mind that today's flare up was the first one of this scale in 8 months).
One last question In your opinion does the fact that they are siblings make any difference / cause any more problems? We have been told time and time again by different people that it is never a good idea to have litter mates but then where we live, in a mainly farming community in Norfolk, most people have litter mates normally working dogs.
Thanks again for your time.