Worth shopping around for an AIP??

ARenter

Thinking of getting an Agreement in Principle (AIP). Is it worth my while applying to different banks/build societies or will they all give essentially the same answer? 

JMA74

Is it worth shopping around for an AIP to multiple banks and Building Societies? ...No, its not. You will spend an hour at least with each lender and there are about 20 decent ones and countless others.  
Will they all give the same answer? - No, absolutely not.  The borrowing amounts and terms can be massively different with the same information.  

You get a broker, you speak to them once, and they find an AIP for you with a lender who meets your requirements.   This is sufficient for what you need at this stage.  
Once you find a property, that broker uses the same information already given along with knowledge of the property you are buying to submit the application to the best lender on that day

It is very very rare at the moment to submit an application to the lender that was initially used for the AIP. Rates change daily or even more regularly than that at the moment

ACG

You will get different answers from different lenders - some may accept you, some may decline you. The amount they will lend will also probably differ. 

If your situation is simple, you might as well just get one AIP. 
If it is not simple, then you still might as well get one AIP but you need to do your research first to help narrow down. 
If you just want to know what the maximum you can get is, then do the affordability calculators, they will tell you that. You can then apply for an AIP with the lender who will do what you want. 

Alternatively speak to a broker, tell them what you want and let them do the donkey work to try and find it.