Hi nutcracker! Nice to see you around here. haven't been much on MN lately so don't know who's doing what anymore....
This is not a reply to your original question but I did want to mention a couple of things to you if I may.
As you well know children develop at different stages and have different abilities until much later on in life. So don't worry too much about specifics here. There is a book called 'What to expect in the toddler years' which most libabries have in stock. it is worth having a look at it. It gives indications of what children are expected to be able to do at different stages -i.e. at 18month, 22m etc- and although you shouldn't take it too literarly it might give you some idea of what expectations to have as regards DS's development.
Definettly make a list of all your concerns and take it along to the meeting with the HV. Don't worry if they seem like minor issues, better to get an answer than not know at all. And nobody will think you're obsessed for doing so, it is normal to have questions for professionals, that's what they're there for.
On the subject of interest in play.
It is a good idea to offer a child a variety of play things so keep doing so even if he's not interested in them. Use the most basic toy if a complex one is too much for him or he doesn't have the patience for it (i.e. very simple puzzles, very large building lego blocks, very simple and colourful board books etc). By succeeding, he will develop an interest in something new and later he will decide for himself what it is he really likes. But you are the one able to provide him with the variety of choices.
If he's so good at physical activity take him to the park lots of times (if there is a decent one nearby), let him and encourage him to climb on the equipment, use the slides etc. When a child is good at something you as a parent need to push him just a little bit further, without him realising it then he'll have the satisfaction of doing new things. Swimming or playing with water migh be interesting for him. If so, offer him various water play objects he can invent games with by himself (empty plastic bottles, boxes, sieves of different sizes, differently shaped foam objects etc, what you can find in the house. give him some paper and make him observe how it desintegrates when it gets wet in the water, or sugar granules dissolving in water, heavy and lightweight objects reacting differently in the water etc.just exploratory play)
Try something new neither of you know if he likes. Try painting and playdough. the messier, the more enjoyable for him.
As for shape boxes etc, use an alternative: pebbles posted through a plastic box with a hole cut in the lid. Etc.
So, what I'm trying to say is: offer variety and observe what he likes/is good at and encourage that type of activity. Keep giving him new challanges with activities he's good at (i.e. climbing). keep it simple, go back to simple games, toys, books etc to make sure he understands what is all about and progress from there on what he's interested in.
What about toy cars? Something else he can play with. Or find a type of toy he likes and encourage him to use it by giving him different types of the same toy (i.e. if it's cars he likes get a few of different colours, sizes, types, get a tractor, a bus etc)
Sorry about the long post. Hope it helps a bit. Hope you're well. Bye. take care.