Recipe testing - Nigel Slater's Tender vol 1 - A rich root and cheese soup for a winter's day

A long rambling title but this is really parsnip soup. I've a mammoth 4-5 inch diameter parsnip to use and happened on this recipe while trying to find my 'normal' one, so thought I'd give it a go.
Soups are always easy to make - in this case basically take two parsnips, onion, garlic, chilli flakes and turmeric, and boil in veg stock. I did encounter a couple of problems with the wording of the recipe though.
As I say, I've an enormous parsnip to use so I'm cutting slices off as I want them - which led to the first problem; the recipe calls for 2 large parsnips. How large is a large parsnip? I'm not a stickler for them, but it's one of those times when weights and measures can be handy.
The second problem - again with the parsnips - was there was no indication of how small to chop them. In fact it seemed to say pop them in the pan whole. Anyway, I chopped them into small dice as quicker to cook, and after that everything went well.
I didn't have single cream, as called for in the recipe, to hand, so stirred in some milk at the end - it was still creamy enough. I also skipped the cubes of cheese Slater suggests adding, so technically mine was just "a rich root soup" but still delicious and different to my normal 'curried parsnip soup'.