I have just replaced my chain and cassette and the chain, not unexpectedly, is slipping when on the largest chain ring. Should I bite the bullet and just get a new chain ring, hold on until the chain and chain ring mesh together, or take a file to the ‘shark teeth’ on the chain ring?

Also, is it normal for this problem only to occur on the largest chainring?

It won’t “bed” just change it… the teeth will have worn to the point where only a stretched chain will fit. Kinda..

What’s the largest size chain ring that would fit on a standard slx chainset? Or is that too difficult to answer without seeing the chainset?

There isn’t one as such. It will be determined by chainstay clearance and the size of the cage of the rear mech. Short cage and you will be on smaller ring, large one and you can have a larger ring. However that said you won’t get a 53 on there!

Your chain is only engaging at the first tooth in line of pull, it’s lying slack on all the other teeth so no wonder it slips.

Tried a similar thing recently on my road bike ended up with chain wrapped round rear derailleur & a phone call to a mate to come rescue me 😳 yeah just get the chain ring