Welcome to the forum, Roland.
You can indeed use the 3-phase sketch to measure a 3-wire system, and the result will be a good approximation. It will not be an exact measure, because only one voltage is measured, the second voltage (because the sketch uses the 3rd phase as the “neutral” and treats the other two as a 2-phase system) is assumed to be equal in magnitude to the first.
What you will need is an emonTx, two c.t’s and a 230 V (Are you sure your voltage is 240 V, not 230 or even 220?) a.c. adapter, and a programmer to upload the sketch.
The sketch will not run on the emonPi, therefore if you want to have emonCMS to record and display the data you need either the ESP8266 WiFi module (plus a 5 V d.c. USB power pack) and a Raspberry Pi for emonCMS to run on as a web server, or you need an emonBase, or you can use the ESP8266 and the on-line service emoncms.org.
If you really need accurate measurements, then I would suggest the same strategy, i.e. treat one wire as the neutral, and have an emonPi (with 1 c.t. and a.c. adapter) measuring one voltage and one phase current, and an emonTx (again with 1 c.t. and a.c. adapter) measuring the second voltage and phase current.
One final note: whichever way you measure, the two “powers” you will read are meaningless, but the sum of the two will be correct (within the accuracy of the measurement, of course).