I mean the additional cost for the CAA to reprint the licence pages and cert of reval.
Now that I am not sure as I haven't heard of that before, why not just renew the me/IR and at your next reval just do the IMC test / SE/IR, or do the IMC test now on the single.
You won't get an airline job without an ME/IR on your licence as it's required for the type rating course. I hold MPA and SPA ME/IR and they are not too onerous to keep current with cross credit and section 6 prof check anyway.