Here's a KYMCO Consumer parts site where you can lookup Super8 150 part numbers and compare to what you need.
http://kyps.kymco.com/kyglobal/F001D.doThere is 125cc listed but it is the US models. You may be able to go in and match your engine code though for specific engine parts. Ask about for a similar site in the UK for 125cc models. If the part numbers match then order away.
If the part numbers are common and the 3rd party part is listed as a fit for the specific part number then you should be good.
As far as the luggage options, I never added anything to my Super8 150 but Shad seems to have a mounting bracket that works with the Super8 150.