I have shot numerous 50/50 in training.
In fact some days it feels so easy.

Then come comp. time. It all goes out the window and I have shot 82/100 in the first 10 shots.

The answer is not to give up!
Enter every comp you possibly can.

Ask yourself.......

Why Am I Nervous?

It's probably due to being old. Knowing that if you can shoot like you know you can, you could win the British championships.

Your just not relaxed enough.
The worst you shoot in a comp at the start, the more stressed you get.

It doesn't make sense, but it happens.

Don't give up.

Keep Trying. Then one day you might surprise yourself.