A was for Austin, but now B is for Bedford

The second lot of paint (the suspect paint) was mixed to suit as the shop had ceased dealing with the original supplier.

Unfortunately I am not sure of the brand, sorry mammoth; I simply wasn't interested in using it again, anywhere!  All I did was return it to the paint shop and replacement paint was re-ordered from White Knight (the original supplier) for this situation, at no cost to me. 
White Knight Rust Guard Epoxy Enamel - no problems with this.

While waiting for the paint to arrive I used some Dulux paint on the cab roof with no issue, even when used over existing paint. 
Dulux Metalshield Epoxy Enamel - no problems with this either.

All the paints used in the upper half were Classic Cream in colour and to date I have had no problems when used over, under, or near any of the red paint.
The red paint has been either Rust-Oleum Protective Enamel Oil Based (Regal Red)  or  White Knight Rust Guard Epoxy Enamel (Flame Red).

Sprayed the Flame Red on the rear doors this afternoon and looks okay thus far . . .  
 

Is that spray cans or mixed paint?
gumpy

Most of the paint was from a paint can, but while having some poor results with a roller I had the paint shop decant some into pressure pack cans for me. These were reasonably cheap and allowed me to create some shine on the lower sections - far better than when using a roller. Although the spray cans were successful I found them susceptible to clogging, despite much shaking before use and inverting the can to clear the nozzle afterwards. I actually had two cans that were left unused for about a month and they then simply refused to spray when needed - one had minimal pressure and the other had absolutely nothing! I have contemplated drilling a hole in these   but really am not that desperate.

I have used a roller with the cream paint, decanting some into three spray cans. It was doing this that resulted in me having to buy the second (bad) batch of paint to finish the cab roof and which I attempted to roll on with disastrous results! Thus at the moment I have about two litres of cream paint left which should allow me to complete the top half.

Last weekend I bought some red White Knight paint in a 250ml can AND a spray can for the rear doors. Total paint expenditure is around the $400 mark to date including rollers and turps.

I have painted probably half a dozen cars in my life, but never using a roller before. It does have some advantages (no over spray in particular) but in hindsight it would have been better using my spray gear from the start. NB I said better - not easier.

So far as the rear doors go: the cream paint was rolled on and the red paint was sprayed on from last weekend's rattle can. The black circle (around the red circle) and the thinner line around the "aeroplane" letters will be by brush - which I am not looking forward to. The word INTAVA at the bottom is still under consideration . . .   

Hope that helps grumpy gumpy?  

I was told recently by a man who should know, it is not the BRAND but the TYPE of paint that causes this trouble.  He told me that if I apply acrylic paint over enamel (on my firewall, as I wanted to do) it will crinkle and craze just as you found, PDU.
 

.??
I typed out a reply that seems to have vanished
Gumpy

As the tattooist said to his client after making a minor spelling mistake with, Born looser . . . 

Acrylic over enamel certainly will.

The guy in the paint shop sold me the first lot, + another can a little later because it was going cheap due to them discontinuing that brand (not included in my earlier comments as I considered that part of my first batch). 

I was aware of the problems caused by mixing types of paint and assumed when he mixed up the second batch of paint he would use similar paint again - this was obviously not the case, oops!  

It goes with my last comment to grumpy gumpy and became a definite "such is life" moment for me.

ALSO  Mrsmackpaul, I'm still chuckling about the downforce comment. Certainly don't need any of that, it's heavier enough already. 

I wonder if your paint supplier might be able to "recharge" your spray cans for you?

Jarrod.

I have asked  about that asw120, but apparently it is a one-off/one-use arrangement and can't be done otherwise they would have recharged the two that I had that lost pressure.

Why did they lose pressure?  Murphy's law obviously because I wanted to use them!?    

One day I might investigate cutting/drilling them open . . .