Is it normal that a small company in the UK does not give payslips and the payment method is in cash?

I started working in the UK -legally- but what it seems strange is that my employer does not give payslips and what they say is that they do not do it because they are rather small -which they are, only 5 staff-. Payment is given in a wage envelope (which it does not seem to be an official receipt or proof of the Groos and deductions of my salary). Also, there are tips that we receive every week, are these taxable and if so how do I go about it given that they are significant (�60-100 per week).?