Things are a lot different now than they were 35-40 years ago when I was little and in tow, but those guys would've used scroll saws and such (in my rural area, the incidence of some guy with a 1500SF shop was small, and certainly not in the circles that worked craft shows - those guys were looking to make money, not spend it).
I just looked at some literature here and on an old price list, clear pine is shown as "Clear pine (white)" next to "knotty pine (white)". There's no price.
I just went to the website of the same dealer and they're still in business, but now their softwood is second growth california redwood.
So aside from tracking down an amish sawmiller, good clear white pine with straight grain is probably not easy to find.
The clear pine sold in the stores here is radiata pine.
selected light colored poplar or american sycamore may also be nice (but sycamore is starting to get on the harder side). But even that (sycamore) is generally just flooring wood here.
I guess some of this is a shame as clear quartered white pine is just wonderful stuff and would make *Fine* looking toys. (I snapped this from the outside of one of my chisel wall racks- close enough to keep the knots out of the picture!!).
IT looks like spruce but the rings aren't hard, so it can be worked cleanly.
(the wood above literally came from one piece stair treads at lowes - $10 each with the pith down the center and the sides quartered. I think they lost their mind for a second and I never saw them there again).
nearly forgot - if you're in england, you're near water (relatively). Boat supply places with "vertical grain softwood for decking or cladding" may be an option. Not sure if they'd do pine or redwood, but they might have light weight mahogany would would also be a nice working choice. It works like butter when it's not dense and seems indifferent to poor technique with power tools, which is usually an indicator that it'll work superbly by hand - you can just cut without fear of big splitouts.