PA38 - You're not looking very hard. Try LCY for a start.
Yes, you should see DLH and VLE E190s going in and out of LCY, though not the CFE Embraers as they don't (yet) have ADS-B.
Another option would be to look at Heathrow on FlightRadar24, where as well as the odd DLH and LZB, you should be able to see Embraers with ADS-B operating most of LOT's flights.