I am due to start flight training at Oxford Aviation Academy in September
If all goes to plan I will get my first job and type rating with a european airline (probably a low cost) and build up my hours
Good for the OP for doing some homework, however I find it particularly interesting that someone who has yet to start training is discussing using a European airline as a springboard into the US market and particularly the regionals - they don't pay much by comparison to even the LC's in most of the EU but that's another story...
Interesting times following many years of so few jobs, that a candidate would contemplate leaving a much coveted jet job in Europe before they've started training - why not cut out all the additional time, cost and effort spent in the pursuit of an EASA CPL/IR and MCC, emigrate to the US and complete an FAA Private/Commercial/Instrument and CFI, build your 1500hrs instructing then apply to the regionals seeing as you still have to go via the regionals to get to the majors?