Count maximum times same number used in a row by criteria

Tricky one to explain, but example attached.

Is it possible to count the amount of times a number is used in succession?

For example if you have in column A the name of the location and Column B a serial number. Can you count the maximum amount of times the same serial number is used in succession for that location name.

I don't want the total count of the serial number just the maximum times the same one is used in a row

Sorry for the awful explanation, the example file should be clear though. Thank you for any help

=max(frequency(if(($a$2:$a$52=$e6)*($b$2:$b$52=$f6),row($a$2:$a$52)),($b$2:$b$52<>$f6)*row($a$2:$a$52))) cse

Hi, again

Thank you for your replies, it's so close to what I want! Is it possible to have the serial value returned as well as how many times it's consecutively used instead of having to input that too?

So the maximum consecutive amount of the same serial value per location and then also return that serial value?

I can do that using a helper column as suggested by Marvin, but is that also possible using a single formula?

i'd prefer UDF
formula with worksheet functions would be huge without helper column