His are bigger than mine!

Some of you probably know that I do the garden for an elderly man round the corner who is housebound. His garden is much smaller than mine and at the beginning of last year he got someone to clear it and build a small patio. They put some weed suppresing membrane down and covered this with bark chipping.
Last spring I planted a few small roses and some other perennials on either side of the patio and everything grew very well. I suggested that he could have a couple of tomatoes in growbags on the edge of the patio where it abutted the fence as that area got plenty of sunshine and seemed to be crying out for something. He agreed and I planted a cherry tomato (Gardener's Delight), a beefsteak tomato and a standard variety (Alicante).
The plants grew well but then we had a very windy spell and although they were tied to canes, the stalks broke on the bigger ones and the crop wasn't so good. Last year mine did better.
This year he has got three plants again, all the same varieties and this time I split the growbags in half and stood them on their end to give the roots more depth then put in sturdy canes much earlier. I had reminded him to water them daily even if it rained and to feed twice a week.
All three plants look as though they will have an excellent crop this year but I only had room for one plant myself, a cherry tomato in a large pot. This is a long way behind his and has fewer, smaller fruit despite the fact that I give it the same attention. The only reason I can think of is that his three plants get an extra three hours of sunshine compared to mine. Perhaps mine will catch up later.