Always Late

For the past three months I have been meeting the train from Bristol that should arrive at Warminster at 18.08 .  I can only remember it being on time once.  Usually it is  between 5 - 15 miinutes late, sometimes more.
If it is so difficult to get this train to run on time perhaps the timetable should be changed -  then nobody would mind?
Is there any other train in the day that is regularly late?

The morning rush hour performance of Great Western yesterday (10th Decmeber) was diabolical. Their early morning empty train from Westbury to Salisbury broke down - brake trouble - and chaos ensued. Why can't they look after their trains better? They cannot blame brake failure on leaves on the line or the wrong kind of rain - it is pure managerial incompetence.