Home DIY

• The reds all grouped together are the loop lives
  
• The greens are the earths
  
• The blacks together are neutrals
  
• The black on its own is the 'switch live' from your light switch.
  
  

edit: incidentally, if your earth sleeving is plain green then your house wiring predates 1977.

to feed your new light you need:

• switched live
  
• neutral
  
• earth
  
  

So your plan seems to make sense.

Remember to use earth sleeving on any bare earth wires. Make sure you give each newly connected terminal a proper tug to ensure all the wires are in snugly.
Bear in mind that the lives in the ceiling will be 'hot' even with the switch off, so make sure you turn off the lighting circuit first, if not already done so.