You can come in Lodz with any level of knowledge (even without reading Bristol GS) but you need to complete everything before Bartolini can issue your certificate (CCC) required for exams. And you do not need to wait 5.5 months for classroom, you need it just for the certificate.
In other words, book your classroom at any moment. For the certificate you need
- to complete 100% of BGS
- to spend 2 weeks in Lodz
- then pass internal exam(s)
- to wait 5.5 mounts from your subscription date in Bartolini