Indeed, channel 0 (868.1 MHz), SF 7, like your gateway log shows you.
But your node's log shows it's transmitting on at least two channels. Given @matthijs' comment when his example sets up the channels:
Without this, only three base channels from the LoRaWAN specification are used
...and apparently lacking anything similar in @platenspeler's example, I assume his code relies on those "three base channels"? Assuming that includes channel 0 (868.1 MHz), for testing just add:
LMIC_disableChannel(1);
LMIC_disableChannel(2);But still then, assuming the base channels include channel 0 (868.1 MHz), some of the node's transmissions should already use that, and hence be visible in the gateway.
Does the node's pin mapping match?
Note that many SX127x modules only expose a single antenna connector and then use the SX127x's RXTX pin and an onboard switcher to wire that single antenna connector to either transmission or reception, hence not needing the LMIC rxtx to control anything. See also Matthijs' excellent documentation (but note that LMIC_UNUSED_PIN is a recent addition, not yet merged into every clone of Matthijs' repo).
Note that it's platenspeler's repo, not TTN's. Minor detail.
http://thethingsnetwork.org/map and http://thethingsnetwork.org/c/london with green being online and blue Kickstarter pledges—but the displayed range is just a configuration.