So hypothetically my driver's licence is lost (quite likely). I'm not in the UK. Is there any way I can get a replacement one from overseas and get it sent to either me, or a friend in the UK who can forward it on?
If you're permanently abroad, then the DVLA cannot issue you a driving licence.
Otherwise, if you are temporarily abroad, you will need to enclose a signed letter with your full name, date of birth, the UK address on your licence, and your address. This goes along with your D1 application and you will get your new licence mailed to you. Applies if:
If you lost both the plastic photocard and the paper licence, do not need to make changes, and have a Visa/Mastercard/Eurocard/Maestro credit or debit card, you will still need to send the letter. However, you do not need to fill out a D1; instead, you can make the request over the phone by calling +44 (0)1792 782 341 between 8.00 am and 8.30 pm Monday to Friday and 8.00 am to 8.30 pm on Saturday.
If you want to be doubly sure that I've got everything right, here's the interactive tool.