You will need to get the codes read mate
But usually the ESP light on permanently on the mk5 platform means the dreaded brake pressure sensor fault
Which mean the hydraulic side of the ABS unit needs replaced, can't replace/buy the sensor on it's own
Depending on service history age and milage VW goodwill are paying for a good chunk of these to be replaced.
But can't jump to conclusions , get it on vag com etc to read the codes.