P-Mode search recommendation

P-Mode search is not defined and different systems may behave differently

As an example P-Modes may be identified in multiple ways. Eg.

1 Using the @pmode in the agreementref - although optional this imo is the most simple approach

2 combination of to/from/service/action - this would fail on mismatch and would return EBMS:0010.

3 combination of to/from/agreementref - ditto

4 Just agreementref

5 combination of from/MPC for pulls

and finally

6 just MPC for pulls