Switching sockets and lights from plastic to metal, earth wire query.

[cataphract]

Hi all, hoping everyone has enjoyed their bank holiday weekend. I hope this post goes in the right place as I've just joined. I'm looking to swap a two way light switch and two double plug sockets from bog standard plastic ones to stainless steel ones, the existing wiring (old colours) has an earthing cable going to the back box but the new switch/sockets have earth terminals in them. Do I just undo the earth from the back box and put it in the front plate terminal or does it need another wire?
The double socket has 2 red into one terminal and two black wires into the other and then an earth into a terminal at either end of the socket with an additional earth going out of one to the back box.
Am I right in thinking that its a straight like for like swap?

The switch is a two way switch so has two cables going into the back box, two red wires out of one cable go to the L1 and L2 terminals and a red wire and earth sleeved wire come out of the other cable going to the common terminal and back box earth respectively.
Again is this just a straight swap and put the earth sleeved wire into the earth terminal on the metal face plate?.

Hopefully I've explained this in a way that can be understood as I'm mechanical trained and don't normally have anything to do with this dodgy electric stuff! ?

As a small addition is there a survey that can be done to examine the wiring with regards to whether the house needs rewiring as I've had a couple of sockets fail and some lights have stared flickering occasionally, however they had new bulbs in not long since, although I'm inclined to think the wires may be getting stretched as I've fitted new metal shades to them.
Thanks for reading and I look forward to hearing some wisdom lol.

 

[telectrix]

Hi Everyone, thanks to everyone who's replied, this is the switch in question, I believe it does go to a jointing box in the loft. So am I correct in saying that earth sleeved wire just goes into the earth terminal that's on the new face plate and the red wires are like for like swaps.?
View attachment 89456

yes. earthing the metal faceplate is mandatory, and as the lugs are plastic, i would add a fly lead to the back box, or leave existing where it is and fly lead to faceplate.

 

[pc1966]

If you can post your approximate location (city, etc, not full address) there might be someone on here that can do a EICR for you.

The sort of things they would be looking out for are covered in the Best Practice Guide #4 available for free here:

https://www.----------------------------/professional-resources/best-practice-guides/

 

[cataphract]

If you can post your approximate location (city, etc, not full address) there might be someone on here that can do a EICR for you.

The sort of things they would be looking out for are covered in the Best Practice Guide #4 available for free here:

https://www.----------------------------/professional-resources/best-practice-guides/

 

[cataphract]

I'm in the Barnsley area of South Yorkshire