Manager Danny Wilson refuses to give up on the duo, with a deal believed to be in the region of £250,000 knocked back, although he acknowledges he must have one eye on potential targets elsewhere to ensure the Robins do not lose out.
"We have put another bid in and we're waiting for a reaction from Celtic," he told the Swindon Advertiser. "The further it goes down the line the less chance we're going to have. But we're still talking, that's the main thing.
"With a bit of luck there'll be a positive answer by the end of the week.
"We're trying to formulate something that will be acceptable to Celtic and the sooner we can get the boys in the better. But if we can't get them then we have to move on.
"We can't concentrate on those two all the time, there are other areas we have to look at just in case we are going to fail there."