Based purely on speculation I’d assume that the relationship between HF & LF drivers in your Barefaced FR800 is probably similar to the relationship between HF & LF drivers in the RCFs, so maybe go with one of them to aim for a closer tonal match. I can’t find the specs re: crossover point in the FR800 but the BF website says the HF driver deals with the highs and high-mids.
The RCF HD32a (the one I have) sells for £818 at PMT and Andertons.
The RCF ART732 (12” version of the 735) is as far as I can tell pretty much exactly the same as the HD32a but in a different (less attractive?) casing and can be found for as low as ~£740
Meanwhile, I’ve just stumbled upon an ART735 selling cheap on Gear4Music for £715 - here. Only 1 in stock. I think it may be a previous generation model but not entirely sure. Makes very little difference to me whether it’s a MK4/MK5 or whatever. The only thing that would put me off it is the size. The difference between the 12” monitors and the 15s is enough to perhaps be a bit prohibitive in certain venues. They ain’t exactly compact!