Most dog-friendly accommodation restricts guests to just the one dog, especially on larger self-catering holiday complexes. The reasons are purely practical, the more dogs on-site, the more potential mess. There is always that one dog owner who does not have good manners and picks up after their pet. It is just about reducing risk.
The same applies to inside self-catering cottages, the risk of damage increases with each additional pet. You of course know your dogs inside out and are aware if they have any behavioural problems. Unfortunately, if furniture or soft furnishings get damaged, the accommodation owner then has the extra task of obtaining replacement items before the next guests arrive.
The breed of dog also matters on cottage complexes, especially where there is a family oriented atmosphere. The site management hopes for repeat bookings and does not want any children, adults or other dogs being terrified by another of their guests. So please do not take it personally when dog restrictions are applied. Some pet-friendly holiday let owners vet their guests over the phone before they decide that your dog can stay and part of that is dependent on you giving them the responses they want to hear. Sadly, much of this springs from previous bad experience.
What holiday accommodation owners want to hear about your two good dogs
So, when you are asked about your dogs, the emphasis should be on how docile and well-behaved they are, quiet (unlikely to bark at night and disturb other guests), how you always clean up after them, how they do not damage anything and that you will never leave them alone in the accommodation.
There are holiday cottages that offer dog-sitting services that you may find useful if you would like to go somewhere that you cannot take your dog to.