Thanks for all your feedback.
Lowering tyre pressure or wider wheels: In this particular case, with 140 km of hills, up as well as down, followed by 90km of flat stretch, losing the decreased rolling resistance to get up that one bastard of a hill wasn't worth it. I simply got off the bike and walked it up the 20 or 30 metres of 20 degree slope.
Smaller front chain-ring: the week before, I had changed my cluster from a 12-25 to an 11-28. To get to 28, they leave a lot of the intermediate ratios out, and going up and down a whole range of differing gradients meant I really missed the incremental changes. I was always hunting for the right cadence and work load. This also applied to the chain rings, which could have been smaller, just as the crankshafts could have been a bit longer, but then you end up with more leg weight being thrown around a bigger circle faster. (Apologies for my reductionist tendencies). John suggested that I look into an oval shaped chain ring, which I think would make a positive contribution, but I've been told that they are very hard and expensive to come by.
Also, leaning further forward was something I tried, but found that tilting the pelvis further forward meant that the thing muscle-mass was closer to seat bottom and when pedalling hard a painful pinching was experienced. Here, I think I will round the seat bottom edges downwards to make the seating area slightly smaller.
This last point is something I pondered on quite a bit as watching the normal cyclists ride by, one can't help but notice the way they shift their body weight from left to ride as they saunter up the hill. We can do that with our shoulders, but it ain't the same, there's nowhere near the muscle mass there to throw around. Perhaps if the seat surface was more convex, one could roll their hips in the same way and gain some benefit?
This then gets back to technique and I had been trying to master the pull/push mode and not just pushing the pedals, but given my shoes were a fraction too big, I ended up with blisters on the soles as well as the heels which meant that I was just back to pushing again. This reduction in muscle utilisation must have meant hills were longer than they needed to be.
Having said all that we did a time of 10.5 hours for the 240 km's which was an average of just under 25 km/hr. The best time was 8 hours, for an average of 30 km/hr. And all in all, despite one minor dismounting, the bike could not have been better. In fact, it was the best ever. Sure, I was the only recumbent rider there, and people did generally look upon me pitifully in the hills, typically most of what I lost going up, I picked up going down. And on the final flat stretch home, many of the buggers were drafting behind me. It's time to get back to that tail box...
Oh yeah, and one more thing, leaning forward to grab the handlebars does leave you in a weaker position, as you have to use your biceps to pull you closer and to then act against your legs. If there were some handlebars, that, like drop bars, gave you two positions to hold on to, one laid back, one sitting upright, but with the same arm extension, it would be easier to heft up hills, I think...
