Engine diagnostics

[Ben]

Hi all, 

I'd like to read fault codes to hopefully pin point problems, sensors etc. I've read that some OBD readers will work, however I've tried 3 now with no success. 
I've been recommended Peugeot planet, but where is the best place to get it?  

https://m.ebay.co.uk/itm/PSA-DIAGBOX-V7-...SwrOtZ0LDv

This is the cheapest I've found, but it says it has a 30 pin plug, and the diagnostics port in the rallye doesn't have that many pins.

Thanks in advance