Many thanks for your patience. I will discuss each clause you have questioned below:
7. This is a standard lay off clause and it is entirely legal – the employer needs it to reduce your hours or place you on unpaid leave in the event there is no work for you. You will see a lot more of these in the future as a result of Covid-19. You do have some rights and after 4 weeks of being placed on lay off you can potentially apply for redundancy
9. Not sure what the issue with that clause is?
13. Relatively standard clause too. You must give them 4 weeks notice to leave, they must give you the minimum statutory length, which is 1 week per full year of employment you have with them, up to a maximum of 13 weeks. They could dismiss with no notice for gross misconduct
18. This most likely only refers to company sick pay. You still get your legal entitlement to Statutory Sick Pay, but this clause basically says that you do not get any extra company sick pay on top of that
21. Have not seen such a clause before to be honest – not surer what they are trying to achieve with it, but query that with them and make sure it is only about future payments, not anything you have already earned and are due from them
Does this answer your query?