Two key points to note before spending any money:
1) there is a difference between a CBT package & a simulator - the first may help in some ways, or may not - it may be a learning tool or just a bit of fun: the second will be fully supported, tested & regulated by the authority which will be issueing your licence, via the licence the training provider operates under. Those supplying the first often use the term without understanding the differences.
2) under UK regs, you will need to undertake an appropriately regulated course at an approved training provider: you may not "self study" & just pitch up to take the exams.