how do I sort out the wiring of a twin switch operating two separate lights?

One for inside ceiling light, one to outside light (works fine). Four cables coming out of wall, appear to be two pairs, going to back of switch. One pair of reds of which one is going to L, is that what is called com?, one to L1 (on outside light switch). Second pair of reds, one of which is going to L (on outside light switch also), the other going to L1 on other switch. Then an additional red wire from one L to the other. All four green/yellows to earth then additional wire from there to switch metal housing. All four blacks to a terminal block? At present the twin plus earth cable, at the ceiling, (checked with my meter) has no power across red and black. All of this only became a prob when I decided to change the original tracking light for a four spot bar because only one of the three spots worked and they were that old I couldn't find any to fit that tracking. Any help would be appreciated.