In reply to andyd1970:
First thing is, age is no barrier!
I can't comment on either of these races, as I have done neither, but I have run in the Welsh hills (e.g. Snowdon horseshoe, round of Lynn Idwal), and I have done some alpine ultras.
Good training is the key to completing an Ultra - whether you choose a longer, flatter, or shorter, steeper one. But probably go for the one you can do quickest, as building up the stamina takes time.
I recommend you run as much as possible off-road rather than on-road. It's much better for strengthening up all the little control muscles in your legs. Make sure you train for downhill at least as much as uphill. Uphill may be aerobically harder, but there is less technique to it, and it doesn't put the same strains on muscles and joints. I like running back-to-backs as a training technique: go out 2 days on the run. Day 1 you run at tempo pace to get your body tired. Day 2, you run slower, but your focus is technique and technique only. What you are trying to do is teach yourself to run with good technique no matter how tired you are. That way you won't get injured and you will finish!
Finally don't overtrain. You don't need to be doing huge distances to train for an ultra. I think the last race I did (a very big one) I didn't run more than an hour - 90 mins a day at the height of my training. But I was running every day.
Enjoy!
Steve