Awkwardly enough, I found the answer moments after posting this but I thought anyone who comes across the same problem as me will find solace in this answer;
It seems downloading the latest version of Internet Explorer is not enough and you must explicitly specify the version of IE to use by adding a new registry key.
HTML fix;
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
... other headers
</head>
<body>
... content
</body>
</html>
Via registry;
Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION for 64-bit or 32-bit only machines.
Or go to HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION for 32-bit on 64-bit systems (It cannot hurt to add keys to both locations if you have them. If you do not have them, you can make the folders yourself).
Create a new DWORD key and name it the name of your application e.g. "myapp.exe" and then edit the value of the key. There are many different values you can add depending on the IE version you want to emulate. I entered 11001 (as a decimal value - 0x2AF9 in HEX) which emulates IE 11 (many more values located at: http://msdn.microsoft.com/en-us/library/ee330730%28v=vs.85%29.aspx#browser_emulation).
If you're using Visual Studio like I am, you'll notice that this method might not even work. However, it does work. You need to manually open the .exe file using Explorer or terminal rather than run the project on Visual Studio.
If you wish to run the program on Visual Studio then consider adding a key for "myapp.vshost.exe" as this is used for debugging.
More information and source is from; http://weblog.west-wind.com/posts/2011/May/21/Web-Browser-Control-Specifying-the-IE-Version.
I hope this helps anyone with any issue regarding your Web Browser perhaps using the wrong IE version as a wrapper or functions are not working as intended.