Thank you for your replies and sorry for the delay in replying, I have had numerous niggles (including complete hard drive failure) to contend with since making this post, nothing serious otherwise just loads of little bits of real life stopping me from enjoying myself
I have had to shelve the idea of a new tripod for a while as finances are not as I would have hoped (Car repairs, decorating, 5 year old son's birthday etc etc) - so having sacrificed the new tripod for a while at least it gives me more time for research.
I agree with Gordon's comments entirely but need to point out that if it works for me whilst in use then I'm daft enough to carry it if at all possible.
My lenses are not the heaviest or most numerous, I have the 18-55 kit lens, Sigma 70-300 apo dg macro and the sigma 50mm f2.8 dg macro.
The kit I tend to carry is my K10D, spare battery, numerous filters, 3 lenses, sd cards, cleanings kit etc.
All of this tends to be packed in my lowepro dryzone rover with hydrapack generally fairly full so all in all it's a fairly weighty lot but I am lucky enough to be fit enough for this not to be a concern, at least for now. I appreciate that I should also look at the future but I'll plan for now and adjust at a later date as and when needed.
The Benbo tripods have caught my attention but I feel that I would be best 'playing' with one first but I may have to make a fairly long journey to do so but this, I think, may well be worth it.
Does anyone out there have experience of a Benbo?