Maris Piper are the ONLY spuds for chips.But there is far more to it than just putting them in the fryer. 1st you need to cut them all the same size about 1/4 inch sq. Next par boil them for 2 or 3 mins , drain them and allow to cool.
When cool you need to dry them . Next step is the 'blanch' them in the fryer set to 135 deg C. Remove from fryer and drain, now turn up the fryer to max 180 deg for the final step 'browning' this should take around 5 mins. They are cooked when they start to float on the surface of the oil.
You can freeze chips at the 'blanch' stage and use them later , I make a large batchs and freeze some.
The oil is important ground nut oil is the best.
You can not make chips in 'one hit' it is a 3 stage process. The par boil is vital as is cooling them down before frying.
Only experience can tell you when chips are 'blanched' correctly it varies according to the size and water content. The chips should be just starting to 'colour' but not brown.