My Rent Has Gone From £50.58 To £56.40. By What Percentage Has It Gone Up?

It is very easy to calculate this percentage.
So here goes, get a calculator and take  £56.40  and divide by £50.58. Which is about ten percent.
Which is the standard yearly increase that a landlord is allowed to increase the rent by, without asking your permission.
This is your weekly rent, I imagine. So I am not sure if you would have signed any kind of contract, but I  think you probably would have.
If you read through the contract, you will probably see that the landlord has a clause in there somewhere, to allow for an annual increase of up to ten percent.
This is to allow for the increase in the cost of living.
Of course, you have also had to bear this cost of living, and would expect to get at least a ten percent increase in your salary.
naturally this doesn't  always happen as a rule, and normally has to be motivated by you.
So let your boss know you have had a rent increase, and perhaps he will take pity on you, and up your salary.