Hi @ruth, don’t think either of these are eligible to be added.
ECR is traded on the ASX1 segment of the LSE and T212 don’t have access to this.
It looks like SXG is traded on the Australian exchange which again T212 don’t have access to.
Have a look here for the initial requirements for adding a stock: Stocks & ETFs requests Help - 
Stocks & ETFs requests - Trading 212 Community