|>>|| No. 8442
You can spend a weekend in one of the larger cities in Germany (be sure to get there early on Friday) and work your way across Chemists ("Apotheke") shops and ask for "Ratiopharm Hustenstiller" as you've been told it'll help your persistent dry cough. That's pure DXM (mg on the package) which the internet can tell you more about. You can bring those back to the UK no problem.
Additionally (but not in the same visit) ask them for "Vivinox"... "We We Knocks". You're jet lagged and just want some sleep and just want the smallest pack they have because you heard it works. That's Diphenhyrdamine. If they don't have Vivinox, you can sometimes point out that "Emesan" has the same active ingredient and that'll do.
If you're dressed properly, don't appear to be in withdrawal (neither of these are common drugs used in Germany) and particularly if you have an accent they'll be happy to help.
Both are very much abusable, and if you want guaranteed pharmacologically clean supplies this is the recommended way. I no longer indulge in DXM, but fuck Corona. I want my DPH to settle down. As soon as flights open up I'm over there.