I bring a shoebox that I have filled for all self-catering breaks. It has:
Small sharp knife
Corkscrew
Veg peeler
Small wooden spoon
Small chopping board
Bin liners
a travel sized bottle washup liquid (a 100 ml airplane size bottle filled at home)
Handful dishwasher tablets
Pot scrubber and a j cloth
Small hand towel (for kitchen)
Box of matches (and a nice smelly candle)
Mini salt and pepper mills (I have big ones at home, but bought the mini ones for travelling - regular spice aisle ones so non refillable)
250ml olive oil bottle that I refill at home before we go (plenty for a week)
Couple of stock cubes (just in case)
Salt and ketchup sachets from McD's etc, sugar sachets from coffee shops (I gather the spares whenever we visit - sometimes we get vinegar, mayonnaise, soy sauce or other interesting things too)
Maybe 1-2 small packs of herbs/spices
Decent handful tea bags, couple chamomile tea bags, bag of proper ground coffee (they have plunger pots) - that'll last us a week
3-4 Bags for making ice cubes
Couple of freezer bags (for keeping things, marinating meats, etc)
Couple of clippits for cartons/packets
We also bring books, board games, pack of cards, and a few DVDs for quieter nights and rainy days. And I bring a nice bottle of bath bubbles for me for 1 night pampering.
Seperately, do a food shop on your way (close by so you can have fridge stuff). Things that are helpful include:
Packet of toilet rolls (4 is probably plenty)
Packet of kitchen towels (useful as napkins too)
Butter
2-3 onions
milk
Bread
Jam/nutella/marmalade (if you like it)
Cereal (if normally eaten)
Dinners for 3 nights (packet of pasta, packet of rice, small bag potatoes, relevant jar of sauce, whatever meat/veg they need - think nice things that are easy - fajitas are fun on hols!)
Lunch things - like meats, salads, (would you make pasta salad or rice salad if you had the ingredients?), tomatoes, cheese, eggs
Snacks - fruit, yoghurts, crisps, biccies...
Packet of rashers and carton of eggs can be used for loads of dinner or lunch or even brekkie options - might you make pancakes one day as you're relaxed??!! And a tin of tuna and another of sweetcorn can also be adapted to a load of different meals.
Beverages - maybe some fizzy pop for in the house, multipack of cans to bring things with you going out (maybe picnic at the lake on fine day), or squash to dilute at home or put into a bottle to bring with you. Wine, beer, G&T - if you normally drink anything like that. (A wine box can last nicely over the space of a week - there are various ones that are 2/3/4 bottle capacity depending on your size of group and capacity to go through it).
Think of things that are easy to prepare, don't get LOADS but maybe enough for 3 full days meals - that will allow you to buy more in the market without spending a fortune, and also eat out a lot if you prefer.
The cooking facilities are ok - there are oven trays and casserole dishes as well as the pots etc. Not loads - but if you wanted to bake croissants from a roll or do a roast dinner - you could. No stir-fry pans though - the only pan is relatively small (but we have been able to use the large pot to adapt).
Definitely bring rain gear - that way if the weather is not perfect, you still get out in it. But there are not great drying facilities (we usually have the heated towel rail in the bathroom draped all the time between towels, togs and clothes needing drying, and things draped over outdoor chairs and BBQ stand when we are not outside). I keep thinking when I am there that a length of strong string/v thin rope would be useful for my shoebox. There are coat hooks and a boot rack in the hall though, seperate to living space.
If you plan on renting bikes anyway, pre-booking them means they give you a lock on arrival for free (otherwise £3 each, I think). If you are bringing bikes, bring your own locks. We usually rent the bikes but bring our helmets (saves £8.75 each).
Definitely agree with comfy casual clothes - doesn't have to be only trackies, but there's very little call for the heels and glamour. Bring plenty for the baby - we never found washing facilities (I bring a travel handwash just in case).
They sell swim nappies, firelogs (for the living room stoves) and disposable BBQs in the parc market - but all are lots better value bought before you get there. The market is good - it has all you SHOULD need and plenty to tempt you too, so I am not trying to say you need to bring it all (especially if space is an issue). They will deliver to the villas (free if ordering over £40 worth) if you are getting lots and some people do that "supermarket essentials" shop as soon as they arrive to be delivered that afternoon, which may also be useful (marketing blurb mentions that they'll put cold stuff into fridge/freezer if you're out).
I can't remember lower age limit for the daycare, but you should check out if that's an option. Not to abandon baby all the time - but one 3 hour session 1 morning or afternoon for just you and DH could be nice to do some sports or something romantic together, and I know that if you book the spa for the same time there is a reduction on the spa treatment cost.
Sorry for the essay, I keep writing as I think of things and it's probably all been said by others by now. Enjoy!