Currency to £ for cart.php and confirm.php

I am new (bet you noticed from the query).

I am following the instructions in "Changing Currency in PowerStore" for PowerStore3. I am using Dreamweaver CS3 to make the changes. I have succeded with all the pages including Admin/Products_Insert.php (thanks Ben Bradley), except cart.php and confirm.php.

Am I right in assuming the files are in the root directory of PowerStore3? If so, I can see many places where there might be a currency symbol, but cannot see any dollar sign in design or code view. However, I can see in the code where it might go, for example

line 584 in cart.php: between the tags, before the start of the php echo statement

<td class="discounts"> <?php echo WA_eCart_DisplayMoney($WA_Store_Cart, $WA_Store_Cart->TotalColumn("AppliedDiscount")); ?></td>

Or am I totally on the wrong track? If so, can someone set me right?

Many thanks, Nick