[devonbarmygardener]

Its worth sieving a carrot or a parsnip bed or raised bed.   Ive read of people doing that.

Love THAT job - NOT!

[crh75]

That combination is exactly what I seem to have - whether that's natural, or down to someone adding an awful lot of sand at some stage, I obviously don't know, cos the allotments have been here for donkey's years; but it's not just in patches here and there 

If you lookup Greensand in wikipedia it talks about an upper and lower greensand belt separted by clay in SW England.  I think it goes through where I live as I have clay soil but there are some very sandy areas (and hugh sand quarries) very close by.