we have a near on 8 month old King Charles
Just checking but assume you mean you have a Cavalier King Charles Spaniel (eg a cavalier)? A 'King Charles Spaniel' is actually a completely different breed.
Not that it matters if you have a King Charles -- they are very sweet too! -- but just wanted to clarify as we don't currently have anyone I think with an actual King Charles rather than a cavalier.
On food -- a spoon of tuna now and then is fine (and healthy!) but don't know if i'd give it every single day, as tuna retains mercury. Sardines can be a better and healthier option, or some boiled shredded chicken; a little cooked mince or liver etc.
Puppies tend to get finicky so I'd not worry a whole lot if a dog isn't getting overly excited at mealtime -- this can be the start of them getting a bit manipulative over food.
As far as it goes, Royal Canin is a decent kibble (far better than what you'd get at the supermarket for example). There are many other options too; no one food is 'the best' and some suit one dog better than another.
We have lots and lots of threads discussing food options so you might find it useful to do a search and see what comes up!
Also there are many threads in the 'Library' section on feeding that might be of interest.
Personally I don't like feeding only a dry, processed food and there are many other options to this that can be researched -- even simply adding some healthful 'real' ingredients to meals is better than a dry bowl of kibble (no wonder dogs don't get really excited at the prospect!). I don't really think it matters a whole lot what kibble (dry food) is fed as long as it's better than supermarket quality. All foods have to meet minimal nutritional levels and at the end of the day, a dry food is such a shadow of the ingredients that went into it at the start. I Just don't think kibble is a great solo option for feeding; convenient perhaps but it's similar to giving a child weetabix for every meal his whole life and offers only a very narrow range of foodstuffs and nutrition. Kibbles ALL have to have vitamins and minerals added because they are stripped out of the actual food ingredients for the most part, during processing -- no matter how expensive the kibble and how attractive the packaging or trendy the name!
I use kibble sometimes as part of a meal during the week -- choosing one with the simplest ingredients I can get with no artificial additives or food colourings, at medium price. I like James Wellbeloved for that.
OK that's my dry processed food gripe over for the day! :lol:
PS my caveat on the dog food analysis website is that they do not declare their own biases or reveal who they are -- which means I cannot judge how qualified they are to pass judgement on dog foods. Some of their opinions reflect some popular food biases that have not been shown to have much basis in any research -- so I would take their gradings with that grain of salt. The site is really useful for getting a good breakdown of ingredients and explaining the different categories of ingredients and what they really mean. But at the end of the day, a dry food is still a processed food.