How to find multiple occurences in text file using VBA?

I have a large text file which is contains the text "_ _Z_1_:_" followed by data such as:

_ _Z_1_:_0_1_3_4_2

Fixed Totaliser Period 1 Reset Report

NET sales 57 £202.05

CASH in Drawer 55 £172.35

CREDIT in Drawer 2 £29.70

TOTAL in Drawer 57 £202.05

There are two occurrences of the "_ _Z_1_:_" text in each file.

I am trying to get the macro to find the "_ _Z_1_:_" and then lift the cash amount (in the above case £172.35) and credit etc.

I have tried using a code to allow me to specify the text file and then used the InStr function but it will only identify the first occurrence.

Any help appreciated.

Shane