I'm sure Chester will always have the Sumatrans as they are such a good display. I did wonder if they were going to phase out the Borneans at one stage, however they obviously haven't, though many people comment on the fact they are often less visible and active. So it wouldn't surprise me unduly to hear that they go out of them at some time in the future.
I do hope they don't. It is nice to have one place with both, and I can't say that the Borneans are no-shows. I always see the females and babies in the netted enclosures, and the only reason I don't see the male is because he's seperated in the old house. They are generally a little more inactive, but that doesn't make them any less interesting.