That is less Qantas and more UK mobile vompanies often not including freephone numbers as free to call. Unfortunately to call 0800 numbers , depending on mobile company, you may need to use a VOIP service ( e.g. Skype )

Some mobile companies do allow freephone numbers as free - need to check calling charges for the mobile company

The 0845 number however is a pain - to be fair, the 08 prefix is standard for non geographic numbers, so it should have been noticeable that it would be a chargeable number

e.g. looking at https://www.google.com/url?sa=t&rct=...a6OI0Ba6728C4s for Vodafone , 0800 numbers can be called for free. The 0845 number is 65ppm - that isn't Qantas's fault