Don't even think about planting potatoes now .. not unless you are growing them indoors in pots to start them off. At this time of year, if they are outside, you will still lose them to the frost.
In about four weeks I will be putting some into 30 litre buckets.
Put about 6 inches of compost in the bucket. Get your seed potato and cut it in any direction splitting it in two. Make sure both halves have at least one chit in them. This will give you two plants. I do this with two potatoes so as I have four halves in each bucket. Just submerge the spuds in the compost with equal spacing. Water them in and that's it. After a couple of weeks the green shoots will come through, this is your sign to put another six inches of compost on top of the shoots and completely cover them. Keep doing this process until the bucket is full of compost, the green shoots will keep coming through.
My first earlies will be ready in 12-14 weeks, although mine will be outside, but they are in a poly tunnel.
When the frosts have gone I will lift them outside and leave them there until I want them. They will store quite happily in the compost for almost a year.
It depends on the size of your bucket as to how many seed potatoes you put in, having done the trick of splitting the potato for the past ten years, I can assure you it never fails and it cuts down the number of seed potatoes you will need to buy.