OK well....
I tried the UHC-S out the other night and found out two things;
1) ALWAYS listen to the posts of other IIS members (specifically NGCLES - thanks again) and READ everything posted about the object you wish to purchase before you buy it!
2) A UHC-S high treansmission nebulae filter DOES work quite well, it brings out the shape and contrast of all nebulae I could see. I looked at M42 in Orion and Eta Carinae as well as the LMC areas and found the greys that I was previously seeing become black in the darker areas and the Nebulae almost TRIPLED in size. All in all, the filter performed extremely well.
Having said that however, I found that the amount of light reduced by this filter frustrated me a little. I know its specifically designed to do what its designed for, but I feel that my money is better spent elsewhere considering my setup. There just isnt enough light coming in my 5 inch scope
and the light that does come in is very messy from where I live.
So... with that in mind, the kind folks at Andrews allowed me to swap it the very next day for a cheaper Neodymium Moon and Sky Glow filter which is much better suited to my needs as it will hopefully reduce the light pollution I get from the city and the moon and should give me more contrast and make things easier to see.
That's the theory anyway, and from reading the brochure included, I feel it's a much better fit for my gear. Add to that the remaining money from the swap allowed me to get a 15mm GSO Super Plossl and a weather station and I am stoked at what I got to replace the decidedly hollow feeling I got from buying the wrong thing in the first place.
I haven't had a clear shot at trying the M&S Ba'ader out yet but rest assured, I will be keen to see the results and keep you posted.
It's also very nice to deal with an establishment like Andrews who are very helpful and courteous to do what they did to save me some embarrassment and potential money wasting on a filter I probably could have kept on standby but probably never ever used with my scope again.

[P.S. - I even found from their website that this is not policy, so now I am twice as happy]
Cheers
Chris