Thanks everybody for your comments&contributions. What makes this a really credible forum is that enthusiasts can tell it how it is for them, we don't get any inane fanboyism stiffling debate - which you can encounter elsewhere.
Cory The nail nick placement will certainly have an effect on the opening action. Many French knives for instance, have nicks placed far forward which makes opening easier due to leverage. French knives often have a relatively easy opening action but are hard to shut, an ideal state in my view. This Queen Sleeveboard has a curious demi half-stop feel about it and the back placed nick on the Master does offer more difficulty in opening, nothing bad mind, but tough compared to the GEC. As for the difference between the knives, the Queen and the GEC are almost identical in length of frame but one is swell-centre and the other Sleeveboard. The GEC sports burly bolsters which in my view are out of proportion to the frame. It's like an overbolstered 'Barlow at both ends' . This shows in the weight 43g for the GEC Conductor whereas the Queen shows 34g both light knives but the Queen has superior bolster dimensions and look, pinched and lined etc. Measuring blade length from bolster to tip of blade the Queen is 5cm or just shy of 2" The GEC shows nearly 6cm or 2 3/8th" and it is broader. So the difference is real and not optical. With the secondary Pen blades both are 3.9cm/1.5" but the Queen is a tad wider. Both open out nice and straight with no droop as these are not Serp frames as on CASE or RR equivalents.
I like single-spring knives and the Queen offers future potential. It's well-made, has D2 which I greatly prefer to carbon....is thin and exhibits satisfying snap. The Conductor is still the benchmark single-spring as it's superbly made, has first rate snap and has a nice long Master blade in a compact frame. Were Queen to tweak this and have a longer bladed Master then from my point of view, they'd be clearly ahead as this is a very beautiful knife.
At the end of the day after buying a knife you should ask yourself just two questions: Was it worth the money? Will I be using it regularly and with relish? The answer in the case of this Queen is yes on both counts.
Here's a crap photo of some single-springs, the colours etc are awful as the light's going but it does show the blade relative to frame. From l, RR Copperhead, CASE Pen, Remington Sleeveboard from the 20s, Queen Sleeveboard, GEC Conductor faux Tortoise.
Regards to all, Will