No pic for me to see either but by the sound of it I would say the components generally match the age of the bike. 6 speed came in around mid 60's. However, Shimano didn't appear until the early 70's, and early Dura-Ace mechs were named 'Crane' so the mech might be a replacement (if it is a Shimano one).
Are the components, hubs etc. in good condition and working well? This will affect their possible value.
I take it you can't remember when you fitted all the components, or were they fitted when you bought it?. Walvale were a good Liverpool builder, I remember them well. What happened to the shop, are they closed now?
Today is the yesterday of tomorrow.