Old school badges have the loops, with a separate pin to fix it. The new nasty badges generally come with a couple of pins that you either bend down or use the little pin clasps on. No difference either way, you'll just need to be a bit careful with the holes to get the loops through.

A beret is a beret for mine, with a bit of effort you should be able to make any one of them look good, personally I'd be steering clear of a leather band, but that's my own preference. If it comes with a liner I'd be cutting it out. I'd shave the inside and the outside to reduce bulk. I used a lint shaver on mine, you'd have to severely f*** up to put a hole in your beret with a lint shaver.
I used a bit of range card as a backing for mine. Are they even a thing anymore? Any stiff plastic will do.

https://www.jbhifi.com.au/home-applianc ... er/958210/ $13
https://www.woolworths.com.au/shop/prod ... abric-care $11

What about the berets that have the leather backing built into them? Its such a f*** around trying to insert a piece of range card, line it up, hold it in place then bunch/cut holes into it and the beret then insert the badge through it without it moving around.

Cutting a badge shaped piece of card and punching a badge through it isn't a herculean task. Admittedly my badge had pins, but still...

Squaddies are issued berets, which come with leather backing on the inside of the beret. This makes sense when you see how (most) British capbadges (hat badge) are made - the capbadge doesn't have pins, rather the rear of the badge has a piece of metal that slides down inside a recess built into that leather backing.

That said, most Brits tend to privately purchase what are called 'small crown' berets, as these tend to be better quality with much less superfluous material, so the material (when pulled down and to the right) doesn't cover half of the side of your head. Have a google at some squaddies wearing berets, you'll see that the flap often barely reaches down to the ear.
Small crown berets are also sometimes called officer berets, as they come without the leather backing. This is because British officers (and WO1s) have cloth or embroidered capbadges stitched on to the beret which doesn't require the leather backing - metal capbadges are for ORs.

The Brits also get a lot of leeway with the shaping (bashing) and wearing of the beret - they very rarely wear anything else. In this respect it's not too different to how all slouchies are a bit unique. The British dress manual may describe how a beret is to be worn, but unless it's on backwards nobody really cares. There is no requirement for the shape to 'peak' in order to display the capbadge prominently.

As in most things, unless on parade the dress standard tends to be a bit more relaxed in the UK, with a lot more appetite for privately purchased kit. Most purchase their own bergens (pack) and webbing. You can wear any boot as long as its the right colour.

POMMY LESSON OVER

As for the beret - Kent are absolutely fine and shape very easily. I've never in my life shaved a beret, it's a strange concept that seems very popular over here.

Boil a kettle, fill your sink and plunge your beret into the boiling water. Leave it for a minute or so, making sure it's soaked. Take it out, and plunge it into cold water. Wring it out, and repeat a few times. This will shrink the cloth material. Put it on your head, shape to taste (or as per the ADM if you've not got any balls) and wear it for a few hours. It'll take shape, then sort out your backing and capbadge.