Spacing breastfeeds when out and about

Me and my distracted baby again!
DD is almost 6 months old and EBF. She has a two to three hour pattern where she is up for 75 minutes and sleeps for 45 to 90 minutes.This is when we are at home, which we have been a lot through Summer, so we are in a groove and enjoying it. When out she can go up to and over 5 hours and shows no signs or interest in feeding, even if I offer and offer.. in a quiet place with minimal distractions... should I be worried about her going for so long? (best spacing at night is 4 hours at the moment). I am not sure that she is just simply not hungry or is she 'striking' because I have been spending so much time at home over the summer with her and she does not want to nurse unless at home. I have considered staying out for as long as it takes for her to show signs of hunger but don't fancy it just for the sake of it...

I am concerned about this type of spacing of feeds because I love BF and don't want anything to stand in the way of it continuing such as bubs not feeding unless at home... we are going on holiday when she is 7 months so we will be out and about almost every day and I foresee that not feeding for such large gaps may affect my supply (I would rather not express for these outings but will if 5 hours is too long)... i don't want to have increased night wakings when on holiday because she hasn't had enough calories during day (we will be starting solids slowly)...

How long can a 5-6 month old go between feeds? I must admit that if she feeds every two hours at home, she does not take full feeds everytime, so I know she could potentially go longer but I feed her on demand..

Is it that I am feeding so frequently at home that I can regard this as a cluster before and after going out or should I be concerned... I've ordered a nursing necklace, can't wait for it to arrive to see if it makes a difference.. she hasn't nursed outside of home for about 6 weeks due to these gaps (which I presume are because she is distracted and not striking) so I am anxious about taking her on holiday..