IG are a sly Market Maker - continually changing the goalposts
I wish I could say something nice about IG Markets, but I can't... maybe I can say a few things.
I have been trading full time now for over 5 years. The first broker I used was IG. They were a very good platform to learn on due to the very small contract sizes. The prorealtime charts are also excellent. Once I started making money I openned an account with MF Global. They were great until they went under. Having lost most of my trading capital I went back to trading with IG Markets, afraid of putting my money into another broker and I perpetuated with them for too long.
I have had many instances where trades have been rejected.... almost all of them highly profitable trades. Speaking with the staff at the help desk they came to the conclusion that it might have been a "flash error". Ok, I gave them the benefit of the doubt. So my solution to the "flash error" was to write my own trading application built on top of their REST API. Using this, I thought great... no more errors in getting my trades submitted. But guess what happened??? you guessed it, rejected trades. I rang up to find out why the trade was rejected and the reason was: "The markets were too volatile, so we turned off the ability to trade in the API". "You what" I said... You have got to be kidding me. IG has cost me at least $20000 in missed trading opportunities where I pressed the button... most of them were very profitable within 5 minutes. If I traded the real futures then every single one of them would have gone through.
It seems to me that the moment they detect that there is a situation where they are going to lose money, then they attempt to stitch it up. This kind of behaviour I find intolerable... so off I go to a real broker, not a broker that has no interest in me winning my trades.
So if you are considering IG Markets, my advice to you is, train yourself up with very small amounts of money... and once you start making money consistently then stop using them.