them separately. Also consider the time of year. Most people aren't looking for bike kit just now, they're thinking more about the expense of Christmas. Bike kit shops have to put on sales this time of year to get people in.
As for the hats, they may well have been worn only once or twice, but how old are they? If they're a few years old then people won't want them if they've any sense. It's like buying a helmet that has been on display - you've no idea whose greasy, nit ridden head has been in it, if it has been dropped and how long it has been out. Ebay is full of dodgy bastards so they're perfectly entitled to not trust you and assume the hats are dodgy. I'd list them separately one more time with an honest history (worn once, 1 year old, made of, etc etc.) and the manufacturer's product blurb. Listing the material they're made of gives people an idea of how long the hat last left in it. If it doesn't sell again, I wouldn't waste any more money listing them again until next season.
I would never touch a second hand helmet and I'd be skeptical if it was a friend giving me an old hat. I've given a helmet to someone before knowing it's in perfectly good nick and I'd wear it myself. Buying one off ebay is a totally different matter as, whilst you may be a perfectly honest person, it's full of people who don't care about selling a dropped but looks good helmet and that person possibly dying as a result and most people are aware of that.