They shouldn't need drilling maybe better to hit with a punch so you don't drill through the bumper if you slip i found that when i drilled mine i was lucky not to drill through - they are also available from Ford but you'll need to fit them and measure how much the bumper sticks out then file some down and glue in when they are perfect.

Look at Andy's thread here will give you an idea Steve https://passionford.com/forum/ford-s...cking-out.html