there is, it's called high build primer. Try your local car paint supplier, shop around you should pay no more than £50 for 5 litres even without a trade discount. Make sure you tell them that you want to overpaint with 2 pack, some primers are too susceptable to the solvents in 2 pack and will react, usually in the form of wrinkling, - it looks as though you have put paint stripper on. Obviously if you aren't using a 2 pack top coat it won't matter.
Apply a good couple of coats and have a look. Sometimes it works well to put a few coats on one after the other, let it all dry, then flat back. This is a very good way of levelling panels and loosing the 'fried egg' appearance of body filler, which is where once painted areas around body filler look like a fried egg! If you get something that has rough paintwork, don't spend days rubbing it all down, only to find that you still have a poor job when you paint it, instead do rub down all the obvious bits and filler etc, but then prime it to see where the areas are that need attention, can make life a lot easier
Feel free to PM, about paint issues or if you want a supplier etc.