PHP: preg_match; Not able to match the £ symbol - php

Question

I've really been wracking my brains over this one, as for the life of me I can't figure out what the problem is.
I've got some data I want to run a regular expression on. For reference, the original document is encoded in iso-8859-15, if that makes any difference.
Here is a function using the regular expression;
if(preg_match("{£\d+\.\d+}", $handle)) //
{
echo 'Found a match';
}
else
{
echo 'No match found';
}
No matter what I try I can't seem to get it to match. I've tried just searching for the £ symbol. I've gone over my regular expression and there aren't any issues there. I've even pasted the source data directly into a regular expression tester and it finds a complete match for what I'm looking for. I just don't understand why my regular expression isn't working. I've looked at the raw data in my string that I'm searching for and the £ symbol is there as clear as day.
I get the feeling that there's some encoded character there that I just can't see, but no matter how I output the data all I can see is the £ symbol, but for whatever reason it's not being recognised.
Any ideas? Is there an absolute method to viewing raw data in a string? I've tried var_dump and var_export, but I do get the feeling that something isn't quite right, as var_export does display the data in a different language. How can I see what's "really" there in my variable?
I've even saved the content to a txt file. The £ is there. There should be no reason why I shouldn't be able to find it with my regular expression. I just don't get it. If I create a string and paste in the exact bit of test my regular expression should pick up, it finds the match without any problems.
Truly baffling.

Answer 1

You could always transform the letter:
$string = '£100.00';
if(preg_match("/\xa3/",$string)){
echo 'match found';
}else{
echo 'no matches';
}

Answer 2

You can include any character in your regular expression if you know the hexadecimal value. I think the value is 0A3H, so try this:
\xa3 // Updated with the correct hex value