I went to see the RIAT departures with my eldest son. But, first we spend two days in London. Our hotel was the Moxy Excel, which was right across London-City Airport. Here's a small impression of what could be seen in thirty minutes. The small airport held one very nice surprise!
1. Of course, British Airways (BA Cityflyer) is present:

2.

3. The E-series is the most common type this morning. Here's a ERJ190 from Alitalia:

4. KLM Cityhopper was also present:

5. Swiss is using Helvetic this morning:

6. TAP Express arriving from Lisbon. As the airport closes around noon on Saturday and re-opens noon on Sunday, this plane was a "nightstopper".

7. The sun was getting around, but still you can have nice approach shots here:

8. JOTA Airways was flying for CityJet:

9. And the big surprise! An Embraer's E190-E2 demonstrator, visiting London-City for the very first time!

Hope you liked them!
Cheers!