Buying a hat online

[Allthegoodnamestakken]

So I need a new riding hat quite urgently but I am nowhere near a shop to try them on. By nowhere near I mean I don't live in the UK, the one tack shop in the country doesn't have any in stock in my size other than non-certified ones that look like cheap bike helmets and friends with horses tell me they buy new ones when travelling.
I have a friend headed to the UK in a couple of weeks who is happy to bring me a hat back if I send it to her parents house for her to collect.
How can I best increase the chances of getting one to fit, my current hat is a 10 year old champion skull cap, the padding is completely worn however so it fits a bit to big.
Would I be best just ordering the current version in the same size? are adjustable helmets actually safe (not doing anything crazy but do hack, jump logs, small courses etc.) Anyway I can figure out my head shape.
I am going to the UK myself in February so can pick up a better hat then if needed but I really need something to tide me over and ideally don't want to throw money away. Although hats are in such short supply here if it really doesn't fit I can probably sell it easily.

If you can't try it I'd definitely go for adjustable. Yes, they're safe, they have to meet safety standards. DD and I had troxel ones for years, till they were replaced after accidents. They are also cooler than most helmets, which is great if you are somewhere hot.

You can get adjustable helmets that meet current safety standards although others on the market don't so look up the most recent standard as they changed fairly recently. Be wary of sale goods as they may be older standard versions. You may get away with ordering your trusty champion. Ive had the same hat and size many times over - maybe find a company that accept returns.

Thanks both, I quite like some of the shire’s adjustable ones and they’re reasonably priced so it won’t be the end of the world if I have to swap it out or sell its as unused.
I would ultimately prefer a peak less one so going to order my trusty champion plus an adjustable and pray one fits well. If both fit I will have a spare and won’t end up in this situation again 🤦‍♀️

Ridicuously I didn’t even fall off, unclipped my hat when I got off and horse spooked and sent it flying off my head onto the concrete floor meters away. My instructor who saw and heard the bang said it really needs replacing especially given its age. Lesson to not unclip it until I’m safely in the car!

I measured my daughter's head - we have a Charles Owen skull cap. It fits perfectly.