How to tell the diffrence between proof coins and their silver proof variety counterparts

This may be a stupid question, but I picked up several 2009 UK proof coins recently and was wondering how you can tell the difference between a standard proof and a silver proof coin. They seem to look similar to me and are listed as the same weight and diameter as each other in Numista.

I know the silver proofs had a lower mintage and were issued as part of the 2009 Annual Silver Proof Set but if those sets are broken up, can you identify the standard proofs from the silver proofs easily.

The exact coins in question are:

2009 Charles Darwin 2 pound proof
https://en.numista.com/catalogue/pieces65578.html
https://en.numista.com/catalogue/pieces16206.html

2009 Technology 2 pound proof
https://en.numista.com/catalogue/pieces113395.html
https://en.numista.com/catalogue/pieces1324.html

2009 King Henry VIII 5 pound proof
https://en.numista.com/catalogue/pieces127163.html
https://en.numista.com/catalogue/pieces17956.html

Honestly I think there is a mistake. A silver proof and that bi matelic although same diameter will never weight the same.

One way to difference is proof coins have a mirror finish compare to normal coins.

Use a neodymium magnet (rare-earth magnet). Keep your coin in a 45° angle and let the magnet slide downwards. On the copper-nickel coin the magnet will slide quickly, on the silver coin it will slide slowly.

If you don't have a neodymium magnet, do the tissue test. Put a piece of kitchen paper tissue over the coin, the copper-nickel coin will be dark, the silver coin bright white:

As per the COA both are the same weight and diameter. Thickness is not given; however, I find it unlikely that the thickness will be that different. Also, as per the official proclamation of the coins from 2008, you will see they are identical in weight and diameter.... Better to try some of the silver tests as mentioned above.

https://www.thegazette.co.uk/notice/E-26540-1101-378

These silver variants don't look like solid .925 at least to me they look like two planchettes one of them gilded.
I think this should also be present on the material field of these pages.

https://en.numista.com/numisdoc/how-to-grade-my-coin-58.html

Thanks for all the replies and advice. I think I have found one obvious difference at least with the 2009 King Henry VIII 5 pound proof. The silver proof edge is plain with text while the standard proof is reeded.

Silver proof £2 coins are not bimetallic. With good photos you can see the difference between a good plated rim to give the affect of being bimetallic.

Thanks, then it should be stated as such in the metal details (like gilded rim or smth.)... right now it says just Silver .925.

I suggest you take it up with the referee for UK coins. As yes technically they are gold plated outer rim

After having it pointed out, I really can notice the difference between the bimetallic rim and gold plated rim. This has been a huge help. Thanks again to all who had replied.