If you're doing a PGCE, this should be enough to get you a job teaching in Spain or another European country.
A PGCE is a recognised teaching qualification and many employers consider it to be equal to a Diploma in TEFL (ie higher than the Cert). So I don't think you need to worry about not having the certificate. However, if the school you work for is run by Spaniards, they might not have heard about the PGCE. In that case, you might need to get the certificate validated or translated. The British Consulate might be able to advise you.
The one thing that won't be covered on your PGCE is the grammar of the English language. It is mistake to think that because somebody is a native speaker of English, that they automatically know the structure of the language. In Britain, we are not taught this in school, so teachers are not exposed to this knowledge until they do a certificate course or start teaching. To counteract this, you could read some grammar books. Michael Swan's Practical English Usage (I think it's published by Oxford University Press) is excellent. A knowledge of the grammar will help you convince future employers.
On the other hand, when teaching young learners, the focus is usually more on activities and using the language rather than on actual structures. Your classroom management skills and knowledge of how children learn will help you get a job.There is a large market for teaching young learners in Spain and your experience with children will stand you in good stead. Make sure you have all your arguments ready when you are applying for jobs. It helps if you write it down.
Having said all the above, it really is difficult to predict and everything depends on which town you want to work in and what type of school.