Late 80s Richer Sounds in London were selling a device called an Enhancer which I wanted for my recording studio.
I begged the staff in the London shop to post one if I sent them money, even offered £20 which was a lot.
I ended up in the shop, pretty sure Madame Tussauds was close, and as I was leaving voiced my thoughts.
The Manager took me to the side and couldn't be more apologetic, he threw me a £50 discount, 5 Maxell Reel to Reel tapes and various leads & cables.
Another unit in the late 80s was a cassette recorder that used a special new form of Dolby.
The shop said they had two and wouldn't post.
I made my way to the shop which was a train ride and two Tubes into a really bad looking area.
i got there as the shop opened and the bloke said "I haven't got any"
So why did you get me here all the way from Stoke? and he just said "because you might buy something else".
I was really pee'd off, made my way back to central London and accidentally came across Tottenham Court Road which was a Mecca for that type of stuff and the first HiFi shop had this unit for £50 less.
To be honest since the 70s I've been to London many times to buy stuff I'd got no chance of getting in Stoke, mainly music gear.