Is that just a standard IEC lead ? If so just get another.
If it’s captive though I’d just cut the plug off & wire a new plug.
I do the latter all the time when I get gear with two-pin euro type plugs fitted - a lot of places (Thomann for e.g. ) now ship such gear to the UK with a great big adaptor plug thing, but it’s honestly easier to wire a new UK 3-pin plug.