garlic planted in Oct

There are two types of onion sets sold for planting, Japanese (autumn) planting onions and others sold for spring planting. You get a slightly earlier crop from autumn sown, but they do not store quite as well as spring sown.
Your garlic should be fine, it usually grows better planted in autumn. It is not quite ready to harvest yet.

Welcome to the forums.

Firstly regarding the onions, there are two seasonal types. What you will have planted will be Winter or Japanese onions. These will mature from about June onwards. However, they re not brilliant storing onions and should be used fairly quickly. They are generally used as a stop-gap between crops of the spring planted ones which you've seen other people put in. These spring planted ones are regarded as the main crop, but unfortunately you've probably missed the boat there.

Regarding the garlic, this will be ready when all the leaves have gone yellow, this is generally not until July/August time.

My autumn planted garlic were starting to look a little yellow at the tips of the leaves about three weeks ago. A top dressing of growmore and a good water soon fixed that. They're all now very green and much bigger.

Both my Garlic and Onions were looking a little brown as well so I gave them a good dressing of Potash and a watering and they are now looking brilliant - I had a couple of fellow plot holders visit over the weekend to find out what I had done to my Onions and Garlic to get them looking so good, I was delighted with myself  :happy:

You'll know what's doing on when you can see the bulbs above ground level. If you can't see one, there won't be one.

With winter/autumn planted onions you may as well use them when they get to a decent size rather than wait for maturity, as they are not going to store for a long time.