UK Car Repair Questions? Ask a Mechanic for Answers ASAP
The p0507 is saying your idle control is showing an RPM higher than expected, and the p12a2 is saying that your high fuel pressure sensor is seeing an implausible reading. Are you having poor idle issues, or lack of power? Also, try taking your oil cap off with the engine running, see if the cap is difficult to remove due to high vacuum, or if the idle gets rough once you remove the cap. Let me know what you find.