[spireitematt]

Is the UK still able to reverse Article 50 and if so how far down the line can we get before it becomes irreversible?

Yes it is but Guy Verhordstadt former PM of Belgium who is a big player in the EU and is helping Britain do the exit talks said if we change our minds now we won't go back to the same deal we had before. We would have to pay more contributions to the EU, we wouldn't get a rebate and we would have to hand over more control and powers.