UK base for experienced FO's are with regards to payscale, regardless of hours you have, even you have 10.000 hours and join as FO, you will be on the following payscale:
SO - 12 months
FO - 24 months
SFO
However if you have the factored hours of an SFO you will be able to call yourself a SFO and wear a uniform with 3 stripes, but you will be paid as the above mentioned scale.
There are bases outside the UK, where you will be able to join directly as an FO or SFO, however UK is not one of them.
But if you have the hours you can call yourself an SFO, have 3 stripes, but you will be paid as SO and FO for the first 36 months. No exception, this has been discussed up and down with BALPA in the past.
This is just the way it is, and if you get passed those first few years, then I would say easyJet is a great company to work for.
And they will give you your chance of upgrade pretty fast, no reason to be upset for this, if you have chosen to go to BA or other companies where you upgrade might take longer. However I know guys who joined BA, and after 18 months got their command upgrade as late as last year.