Our Macs are in the hands of DHL now not Apples, its up to DHL when they deliver them.
Not really. DHL will only deliver based on the requirements that Apple asked for and paid for. Saturday delivery is usually extra and if Apple doesn't want to have Saturday deliveries as standard, then they will not have paid for this. Ideally we should have the option to pay DHL extra ourselves for a Saturday delivery if it would be faster but there is no option for this. Now Apple *might* have paid to enable Saturday deliveries but I wouldn't get your hopes up. Realistically, Monday is the earliest I think we're likely to start receiving our machines.
Edit: Just would like to add, as a counterpoint to what I wrote above, that DHL
have been known to deliver Apple products on Saturdays. It looks like for some product releases on Fridays (e.g. iPhones), they've delivered pre-orders on the release day Friday or the following Saturday and missed deliveries on Fridays were automatically delivered on Saturdays. That was the case for the iPhone 12 release in 2020 and the 13" M2 MacBook Pro released in 2022. There may be more examples but those are the ones I've found so far. However, that was for non CTO orders, i.e. stock already in the UK, so delivery instructions might be different ('launch day' release products often have separate rules).