Fx operating hours for overseas transactions

Hello I am under the impression that the best rates will be during the fx working hours? So Saturday and Sunday should be avoided because they are closed. Is that correct?
Also I see there are differing hours for the differing operating ones. I am currently in Cambodia but from the UK and use Pounds to top up . so I assume that the 8 am to 5pm working hours for the UK fx is the one I should care about?
So basically for best rates i should make any overseas foreign transaction between Monday to Friday (during the UK operating hours), between 8 am and 5pm GMT? Is that correct?
I assume the other country fx hours are for those who use other foreign currencies??
Thanks in advance.

During the weekend (Friday 23:59 - Sunday 23:59 GMT) as the Forex markets are closed, we take the rate from Friday 23:59 and apply a markup of 0.5% on major currencies and 1.0% on other currencies. Please be aware that we pull rates from our provider, and they are obligated to present us with updated rates whenever they are informed of a change from one of their suppliers. This means that the weekend rate may fluctuate and not be the same as the exchange rate we use from Friday. For illiquid currencies like Russian Ruble and Thai Baht, there is a 1.5% markup on weekend.

The above hours are all you should avoid.
I’m still not sure about Bank Holidays - my guess is UK Bank Holidays carry the same penalty but confirmation would be nice.

Thanks for the help but what about Bank holidays? :grinning: