We are hoping to buy a holiday home in

Impossible to say your yield, without knowing your trees, age, conditino etc.There is no reason why you shouldnt do it yourself, it depends if you want to come on holiday or to work!  

Ah the people where the neighbour currently looks after them.... We know people that have 32 trees on about 1HA of land and they struggle to look after them despite being over here almost on a monthly basis. They also have a neighbour cut or scrape the land 2-3 times per year (depends on the rain). As to yield I really can't remember how much they get, but it is enough for them and they use quite a lot. On that same subject, our consumption of olive oil went up near on tenfold when we moved to Italy. We live here most of the time and know our neighbours quite well and watch them look after about 50 trees, we have none and watching them, we would not contemplate getting any. We do grow everything else imaginable, but olives are out... Just do a Google of "olive oil yield per tree" , this LINK from the result gives a good idea what is involved. The detail it probably misses out is how do I get my picked olives from the house to the frantoio (press) , oh and you have to be there at a certain time to pick them and then get them to the frantoio....