Hello David again,
Sorry to hear of your ongoing problems. Without being critical, I'm guessing you are not really spanner wise!
Nothing at all wrong with that, and great that you seek advice, and the best advice I would give you is to foster relations at one (smallish?) garage in your locality that you hopefully learn to trust and respect. They will be your best bet in looking after your best interest. Not sure how big the company you work for are, but if of some size and this garage is local to your workplace, then usually they tend to depend upon a good reputation, since bad news travels fast in a small locality.
From your part David, what you need to do is to look after the car you have, to make sure it looks after you!
OK, not very spanner wise, but make sure you check the oil and water once a week ( "I refilled it a couple of weeks ago" is just bad news!) Check your tyre pressures once a month - and so on. All very basic, but well worthwhile.
Yes, I know there are more interesting things to do, but.... End of advice! - and good luck with getting it sorted as best and most economically as possible.
Kind regards,
Gareth.