So it works out that, if 100g of dried pasta is considered a portion. Then 240g of cooked pasta is a portion, I couldn't have eaten 240g of pasta even when I was 18 stone

that's 75g of carbs from 100g of dried once you have cooked it

I cooked 116g of dried which made 279g, we had half each so I had 43.8g carbs just in the pasta

Slightly more than the 18.1g carbs it would have been if only it was calculated from the dry weight.
Still it is only a one off so no harm done , a little of what you like does you good so they say