You can't do them both combined.
You need the ME(P) to take the ME-IR SPA skills test.
ME(P) skills test is a rating and done by a local examiner. Normally circa 300 of her majesty's finest.
The IR is managed by the CAA and fee details are at
List of Official Record Series 5 - Scheme of Charges | Publications | CAA - under professional rating tests. (I'm not going to do that much leg work for you
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