Why not buy just one or two boxes of mince pies (depending on how many people you are expecting to pop in!) and put them in the freezer? That way, it's out-of-sight, out-of-mind (hopefully!) and you can always just pop them in the microwave for a couple of minutes when your guests arrive. They can then have hot mince pies whilst you look like the perfect hostess (and maybe even convince them that you've just made the mince pies for them! - It depends on how cheeky you are!!). Also, if you do feel like giving in and having one, you can just microwave one whilst not having the excuse of 'well they're open now and I don't want them to get stale... I'll just buy some more if we have guests!'. Also try writing the syn value on the box... 11 syns per mince pie (approx. - depending on size or brand).
How about buying just the small boxes of sweets and only opening them when the guests arrive? (If you put them in a bowl, your guests wont know the size of the box (in case you think it makes you look tight - That was my excuse for buying a tin!)). If you want to buy a tin (it IS better value!...), open it JUST before your guests arrive, rummage around for your favourites and put a limited syn selection to one side - just for you. That way, when your guests are tucking into the tin, you can say "I've got my favourites here! - I know what you're like for pinching all the (insert favourite chocolate choice)"
Make a syn free base for mulled wine (heat up some syn free cranberry juice, add a mulled wine sachet, a couple of slices of orange and I add a dash of sugar-free vimto for some sweetness) once it's made you can add the red wine to the glasses and top up with the syn free mulled wine base. If anyone asks - it's better as the alcohol isn't reduced!!! This way, you can always have the 'same' as them (whilst saving more syns for chocolate!) or add a measured amount of red wine and track your syns.
If you're thinking more along the nuts line, don't buy a packet, but buy nuts in shells. I know it's not as elegant as pre-shelled (and you'll be finding random bits of shell well into the New Year!) but it takes longer to eat them, it's less tempting in between visitors and it's a bit of entertainment watching men trying to be macho and breaking walnuts without a nutcracker!!! Check the healthy extra B list, if you can save your hexB choice until the guests come, I know that some nuts are on the list.
Something I've not tried yet.... Using the HexB tortilla wrap, slicing it into smaller pieces and cooking it in the oven until it goes crispy. I'm thinking of trying it with some syn-free salsa... an option when everyone else is dunking Doritos or Pringles!!! In an emergency, I think that Melba toast is only 1/2 - 1 syn per slice. I'm also making a couple of syn-free dips to have in the fridge, ready to go with some crudite incase people are feeling more 'savoury-snacky'.
HTH