One idea I heard for toddlers is to blow up a packet of balloons and put them in a big box wrapped up - they think it is fantastic.
If you are making gin how about chutneys and pickles? One I make is cheap, and not a pickle or a chutney but feta cheese with herbs.
Buy the cheapest feta cheese you can, or Lidl pretend, and a packet of mixed dried herbs and a bottle of oil - olive is best but rapeseed works too.
Cut the cheese in to chuncks about the size of a match box. Empty the herbs on to the worktop and press the cheese on to it, it will stick to the cheese turn it over so there are herbs on each side - put in a jam jar and cover with the oil.
Cheap knitting needles (charity shop) with a ball of yarn and a pattern for a scarf?
The various wine clubs (Virgin / Naked) usually have offers on a first case, could you afford a case to give as a joint present to all the adults?
Board games can make fun joint gifts, or you could get something like a murder mystery for you all to play one day (assuming you are going to be there for a couple of days).
If they do not have a dishwasher where you are going wrap a bottle of dish-washing liquid up with a note saying you will do all the dishes on Xmas day. Then do them.
Charity shops are good for books and DVDs. Is anyone off to uni next year? A set of charity crockery (all mismatched) would be good - most students have ikea stuff and it gets mixed up.
The pound shop currently has spider led lights but you can take the spiders off and you have plain battery powered LED lights that might make a fun gift - can be put in a jam jar as a lamp.