Of course not. UKMix's server has been straining ever since the ATRL invasion of 29.04.1995 - even those with the highest end Acer's running on Windows 95 have been struggling.
UKMIX merge part definitely is joke, although there can be possible rule changes in mind, but not because of forum merge.
Real forum merge is technically very hard to implement without ****ing up data.
In similar situation solution could be creating two separate web sites on one server, but that will no way affect ATRL forum. In this case there would be completely separate forums.