It's an interesting point Philip. If just just used for shooting and edge now and again the weight would be of little issue. Use it to take boards from the rough sawn state to finish planed in any volume........https://www.youtube.com/watch?v=S5A-vz8ptNU......
My measurement was wrong. The (my) Stanley No8 is 8lb 2oz. My Marples No.7 is a shade over 8lb. (that's me and metric- can't estimate. ) So not much difference.
Thanks. I had never come across Inter Tools before. £239 plus VAT. Interestingly all of the Clifton bench planes are much the same price, irrespective of size. I presume they all need much the same work and finishing and the variable cost of different size soles in minimal.