I have been reading this thread now i take it all the figures quoted are for London' low emissions zone .
Glasgow city centre goes live on 01 st June 23 with really strict limits which no zed 3 will be new enough.
For petrol you have to be Euro 4 or newer ( zed 3 is euro 2 and 3 )
Even early z4 won't be compliant euro4 is 1st jan 2005 on
And for diesel Euro 6 ( my 2015 skoda superb euro 5 )
Fines steep
Within a rolling 12 months period
1st offence £60 ( halved) if paid in 14 days only for first offence
2nd offence £120
3rd offence £240
4th offence £480 ( capped)
Stephen.