I hope you've had more success from the hospital regarding dates and information over the few days since you posted this. I wanted to reply as my son also had this issue although it was one rather than both, and at the time I felt that he'd been forgotten about and basically ignored until I marched to to hospital one day to demand answers.
My son was diagnosed at birth and I was also told 1 year and then 2, it seems that 2 years is the usual age as they like to give things a chance to sort themselves out. My son had an ultrasound when he was 18 months after I pushed for something to be done, I'd been requesting this for around a year at that point because we didn't know if it was undescended or whether it was just not there. I felt that they were fobbing me off, how did they expect things to sort themselves out if they didn't even know if it was there in the first place?
Anyway, an ultrasound was inconclusive so they organised an exploratory operation whereby they would either bring it down if it was there, tie the short blood vessels to cut the blood supply off to allow it to be brought down if it was tied, or to ascertain that it definitely wasn't there. More phonecalls, communications etc and they eventually sent us an appointment and the operation was done.
They found that it was there but the vessels were short, so they were 'strangled' and left it with the plan that they would give it 3 or 4 months and then bring it down in a second operation. They then left us 6 months, despite lots of phonecalls and emails asking for a date. One day I marched down to the hospital, ended up getting hysterical with worry that things were going to be made worse by the first procedure being made worse by not being followed up. The consultant agreed to see us, and explained that it was fine but he'd organise a date for us which he did.
The second operation was done, the testicle was brought down and my son recovered quite quickly but the bruising was more severe than I was expecting. We just kept up the painkillers for as long as we could but he wasn't bothered by any of it. He then had a follow up after 3 months when they deemed it a success and sent us on our way. All we've been told is that we have to make sure there is nothing abnormal going on and if there is we have to see our GP.
So all in all, it was fine in the end, but the stress from the way it was all so lax was awful. Please keep making a fuss and demanding a response. I'm not sure if any of this helps but thought it might be good to know that it seems to be common, both the issue and the way in which its dealt with. My son is almost 6 and has been fine ever since, he was 18 months when the ultrasound was done and then 2years 6 months when the first operation was done and 3 when the second one was done.