You need the forth loop connector normally one can change the block to 4 way. This is the problem with the cheap imports they are not designed for our wiring system.
The ceiling rose is a duel purpose both holds the lamp and works as a junction box. If you need to replace then if replacement is not duel purpose you need two separate items.
The junction box should be accessible if it uses screws as vibration can cause screws to become lose but there are special maintenance free types with push in cable connectors spring loaded these can be inaccessible.
All electrical boxes need a tool or key for access putting a junction block in any box with a screw holding it closed will do but following the rules wrapping the junction block with tape will not comply as it can be removed without a tool.
However some times a little common sense is required and as long as any one at a later date removing a floor board and feeling around is not likely to touch bare wires most people will use tape.
I have heard it said you need a knife to remove self amalgamating tape so that's OK. Clutching at straws really but I will with all electrical job do a risk assessment. How likely is it that it will be assessed from above. And of course hard to remove floor boards without a tool.
Connect your earths to the 'E' terminal
Get a plastic connection block and connect your two reds in to that(this will become your live loop, feeding a live to the switch)
Then you should have a black that comes from your switch (this should be sleeved red and is your switch live) this will terminate at the 'L'
Then the other black to the 'N' terminal.
In the end I had thought about it and had done exactly what kbrownie said even before he said that (hehehe) and it works.
Ericmark: thank you for your answer but with all respects I wouldn't define cheap imports whatever is used in all other countries.
Sometimes I think the requirements in Britain are obsolete and unnecessarily strict (in bathrooms, for example).
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!