OK, success!!!
I didn't need that multiloader in the end, just used 5.33 instead but needed to click 'boot change' before anything else and load the boot files in the new fw, then selected 'full download' to load in the other files....
See picture below for settings required to get things working......
Then it's just a matter of following the previous instructions on page 5 to put the phone into boot mode, remove sim etc and connect up the phone to your PC and hit 'download' on Multiloader above.....5 mins later you'll see the new bootscreen (F488 Samsung) loading up.
BEFORE anyone rushes into this, please understand that when the phone starts up it will be in Chinese! all the menus etc BUT there is simple way to change to English (same as changing langauge on regular english phone, so check that out beforehand if u wish or follow.........)
1. From Widget screen hit bottom right button (menu)
2. From Menu hit bottom right icon (settings)
3. Select 4th icon down from top on resulting page (phone symbol with cog)
4 Select top icon from next list (Aa)
5. Select top (1) from next list
6. You'll than see 'English' second down on that page, select and hit very bottom right (in menu bar, save) then OK on popup if needed.
7. Phone language is now set to English.
Of course you'll need to set up your Browser & email settings to whatever your network setting are. Took me 5 mins to figure things out.
The result is a much more responsive phone with a few more settings as far as I can see too, most but not all of the menus are much faster but there is still a little lag on a couple.
Thanks to kms for posting the latest fw, much appreciated.