(Solved) UEFI and the missing Grub Menu

[Cinammon32]

New computer for the first time in 10 years. Asus ROG Maximus X Mobo. NO Windows! Bloody UEFI!
I have no idea what I'm doing here.
Mint 18.3 KDE installed easily from a usb stick, but no WiFi found. Realtech rtl8822 built-in.
Followed instructions at https://askubuntu.com/questions/926364/ ... -on-ubuntu and got that working.
I didn't need to install the 4.14 kernel but I didn't know that initially. Now I'd like to remove it.
Now the problem . . .
The Grub Boot Menu never shows up! A cold startup or a reboot goes directly into the load sequence and I end up at the Login screen, which is fine, but I can't figure out how to restart with another kernel so I can remove 4.14 which is not playing nice with virtualbox.
I've got Fast Boot turned off as per a suggestion I saw somewhere, and I think i'm booting in Legacy Mode. I've got Secure Boot turned off in any case.
Suggestions happily entertained.

[Pjotr]

Repeatedly tap the Esc key directly after the BIOS window disappears. Keep on tappin' until the Grub bootloader menu appears.

Older kernels are to be found under the Advanced section.

[Cinammon32]

Thanks Pjotr, that worked. Sounds like a bit of a kludge but if it works . . .