I have had raises but no updated contract/official documentation, only communications via Slack.
A little background: I have been working at this company for around 9 months now and in that time I have been offered two raises and a bonus. I got offered the job through my line manager because he is a friend of the family I got chatting to about looking to switch jobs last December. The company is very small <10 full-time employees, it has been going for around 7 years and is doing really well.
Raise 1: when I joined the company I asked for X and it was accepted. X is written in my original contract. A few months later I noticed my tax code changed (UK) and I had a little dig around and it's because I moved into the next tax bracket for the year so they needed to recoup, this turns out to be because I'm actually being paid X+~7% (they basically rounded up). I immediately contacted the founder (who handles pay) and told him the mistake and he turns around and says "Oh I thought that was what we agreed! Take it as a bonus/pay raise for doing so well." Great! I thank him and ask him to email me confirmation of this with a new contract. He sends one across on Slack. I have repeated my request multiple times with no luck, he says he will and never does! NB: It's a permanent pay raise, back dated to the start of my employment. He called it a bonus/raise in the messages though.
Raise 2: Typically Christmas raise (but very substantial) and the offer of a bonus (no mention how much). That was just before Christmas and I haven't heard much else or had an updated contract/confirmation via email of the bonus.
Knowing my company, my next paycheck will have the raise and the bonus will just appear in my account at some point (possibly added onto my paycheck).
I'm concerned about the future. They are looking to sell the company at some point and I am worried that someone will try and "reclaim" this money.
My question is: Is there anything else I can do, outside of continuing to ask for the proper documentation?
Do the slack messages (all of which I have screen grabbed and saved externally) combined with my pay checks which clearly state how much I have been given, constitute as enough evidence that I was legitimately given the additional money by the company?
P.S. we have no HR