Q:

Regex to match SINXX11-111111

What regex would search for patterns of:
(these 3 letters) (any Two letters) (any two numbers)  (a -)  (followed by any 6 numbers)
SIN               XX                11                  -      111111

Eg:
SINDE19-008765

My attempt so far is 
re.findall(r'SIN^[a-zA-Z]{2}\d{2}/-/\d{6}')

but this isn't returning any matches. 
For context, this will sit in the following code to pull matches of this pattern out of a concatenated bank statement row. 
Bank_Statement['TIDY'] = Bank_Statement['CONCATENATED'].map(lambda x: ','.join(re.findall(r'SIN^[a-zA-Z]{2}\d{2}/-/\d{6}', x)))

A:

The ^ means start of the string, which you might put in the front of SIN Your pattern also contain /-/ which would match that literally.
Your pattern could look like
^SIN[a-zA-Z]{2}\d{2}-\d{6}

Regex demo
Another option to match any 2 letters could be matching a word character except an underscore and digits [^\W_\d] using a negated character class.
^SIN[^\W_\d]{2}\d{2}-\d{6}

