1. You should provide your full history since you entered the UK. This is because your application can be rejected for failure to disclose your details of your history. Ultimately, it will make no difference that you did n't have your WRS as it is only the last five years which are relevant. However, as the Home Office will have your details on file if you were paying tax, you should disclose the lot. Otherwise your application will get rejected for being false and not disclosing everything.
2. Be aware that you can apply for dual UK Polish citizenship after five years in the UK. However, you need to be able to show that you were visa free in the uK FOR THE final year by having a Permanent Residence card for that final year. Here is a link to the forms for getting a permanent residence card https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/505032/EEA_PR__03-16.pdf
3. I would advise you to apply for UK citizenship if you intend continuing to live in the UK, given that the UK is leaVING the EU. It is perfectly legal to have both Polish citizenship and UK citizenship at the same time.
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