i have an 8 month old cross rottweiler bullmastiff who weighs 51 kilos. i feed him arden grange classic junior. the recommended feeding chart only goes up to 45 kilos. i am giving him just over the reccommended amount for a 45 kilo pup. he is still hungry after meals and is scavenging, eating anything from socks to paper. would it be ok to feed him adult food? he is not overweight but is lean and muscley and is growing very quickly.

I tend to ignore food to weight ratios and go by "if you can see his ribs when he moves give him a little more and if you cannot see his ribs then reduce his food".  He is probably still growing and will be for another couple of months so if you think he is really hungry then give him more - you could always give him a mixture of raw carrots, cauliflower etc to chew if you really think you are feeeding him too much.

My 18 month old bitch still has more to eat than her grandsire in spite of his being about 16 Kg heavier than she is as she just runs it off, as soon as she starts to calm down a bit then I will reduce her food intake to closer to that of my other adult bitches which is between half to two-thirds of the male's meals.

I would stick with the feeding tables for a few months, yet at the same time supplement with some ground meat or chicken.  I recommend stick with the feeding tables, for when you feed a commercial kibble no matter how good the kibbles claims to be, chances are it is inadequate from a animal source protein standpoint.  I looked at your ingredients, and the 1st and 5th are meat source, however the 2nd, 3rd, and 4th (rice flour, ground corn, beet pulp) clearly are not.  This indicates to me the ratio
between meat source and gluten source is 50/50 at best; therefore use
caution.  If you feed more than the recommended feeding tables indicate,
bone mass could grow faster than muscles tissue.  Slower tissue growth
could lead to problems setting up the dog for future trouble down the road.  That is the reason during growth, many vets and dog food companies alike recommend stick with the feeding tables (essentially an admission they know darn well the food is inadequate).  When your animal source protein levels increase to say 80% of the protein core (ie., 26% protein food, 80%+ from animal source), you can then can ensure adequate tissue growth alongside bone mass.  Therefore, always stick to the feeding tables, but if does seem to be enough to satisfy supplement with your poultry meats, fish and beef.  If you can find a good deal on chicken legs and wings, boil until the meat falls off the bone easy, chop it up and mix it right in with the kibble.  Raw may be more beneficial from a nutrition standpoint, but I am one of those who feel the nutritional benefits gained are not worth the other possible risks.

In regards to your question move into the Adult instead of the junior, I think you would be ok to do so being your pup is now 8 months, however note you losing a few percentage points in the protein (2) from the junior classic to the Adult classic.  If you go with the Lamb and Rice (again Arden), at least you're keeping the protein the same as the Junior at 27%. No matter which your dog will benefit with the addition of some extra meat base rations.... I would also pass on the carrots and cauliflower.