Would I need to find another examiner for the test
Yes
Under EASA an Examiner is not allowed to have had any involvement in
a candidate's training for initial issue of a rating.
The IMC not being an EASA rating does not matter - especially as even
though you will apply using an IMC application form you will be issued
an EASA IR(R)
NB: Above assumes you hold an EASA Licence, or a Licence (eg JAA) that
will need to be converted to an EASA Licence.