2019 St Line retrofit sensors

I'm based in Ireland. Most early model (2019/2020) St lines all have the reversing camera as standard, no parking sensors (poor product decision IMO)....in the MY21 they have sensors now. My parents are looking at a 19 one without sensors. Like many fanatics here, we are fastidious and I have seen cars in the past with sensors retrofitted and sound like they out of fisher price. I imagine its a big job, since the bumpers are body coloured and then the sensors and reversing camera lines will need programmed but basically we would want the car the exact way it would've been had the sensors been specced from factory. Alot of places will tell you oh its ford genuine but I'd be concerned about the finer details and speed and accuracy of the actual sensors. Anyone know a rough cost and what things to specify to the garage. Also, any specific Ford garages who have done such jobs before would be happy to travel to them. We are along the border so even ford dealers in the north (other than Pat Kirks)! :)I'd rather buy the car, bring to someone familiar with the job even though will cost abit more rather than let the garage we buying from (non ford) start trying it and then make a balls. Thanks in advance.