A warm welcome to Flyertalk, both to Smiley2 and theox.
I hope you'll find the site a useful resource, and look forward to reading your contributions.
45mins at Doha is perfectly fine (the MCT used to be 35mins such was their confidence).
In terms of your potential brisk stroll through the airport, one suggestion (to avoid the pricey Al Maha option) would be to book Assistance Support.
If the airport know you're coming, they will push you/shlep you by buggy to Security, and then the next gate. Once you're on the ground, the pressure will be on the Ground Support, and they tend to be very helpful.
Safe travels, and enjoy FT!
M