Hi Simon and Welcome to the forum, you might want to have a look at the following FAQ which explains where everything is
Welcome to Benefits and Work I would expect you to get a decision letter in 2-4 weeks. I hope the decision is what it should be.
When your PIP claim will start depends on whether this is a transfer from DLA or a new claim.
If this is a new claim, it will be dated from the day you phoned to initiate the claim.
If you are currently on DLA, the PIP decision will come into effect 4 weeks after it was made and the DLA will stop at the same time.
If you have any further questions, please reply to this message and we will do our best to help