Hi I am afraid I am still working in Photoshop 6. Probelm being when I input a specific pantone colour into my file, it's values are converted to the values of another colour. I believe this is a colour management problem! Any ideas?

It's not a color management "problem". It's standard application behavior: if you choose a PANTONE color in a CMYK file in Photoshop, or RGB, it is automatically rendered according to the default CMYK or RGB profile chosen in the application's Color Settings. With very few exceptions, that alters the appearance of the PANTONE color itself from its intended one.

If you wish to preserve the integrity of the original PANTONE color, you must use its Lab coordinates. You can do that in Illustrator and InDesign, even within CMYK or RGB files. But, in Photoshop, only working in the Lab color mode will preserve the integrity of all PANTONE colors.

the pantone color values have changed many times since version 6.

the only way to be current is to run current software and even that goes out of date fast.