Hi
On the chip front, i know that the the tv chefs twice fry the chips, firstly in low heat then leave to dry and cool and later finish in high heat for a few minutes. I am not sure if the B.I.R's do it but i know a lot of low rent cafe's do it and it tends to makes for a sloppy chip if done wrong!! The local kebab shops just bung them in from frozen as quite thin cut!
As to the potatoes, the important thing when boiling is to very gently simmer as to not break up the starch molecules which makes them slushy! I usually bring the water to the boil, add the potatoes with some turmeric and panch poran and turn the heat to low. I then check on them every few minutes!
If I get a chance to participate in this test I will cook in only in water only unless stated in recipe.
Regards
Barry