Help GPRS symbols

[smurph1]

Can somebody tell me the GPRS codes on HTC One M8 phone, I regularly do internet trawls for this and fail miserably, why is this so hard to find?
Is it network provider dependent? As they amend the operating system, if so mine is Vodafone UK.

On my phone I see on different occasions:
Signal bars with no symbol / E / 2G / H / H+

I write them in this order, but am unsure if this is order of superiority, please advise order and meaning?

Is there an online guide for this that I can't find?

 

[kevindroid]

Edge/2g/hspa/hspa+ these are data network technology as these symbols change you will see speed changes

 

[smurph1]

So that is the correct order in increasing data speed?
Where did good old G go?
And is H+ 4G?