Personal statements are wierd things. In most instances the PS itself (unless some serious red flags) will not have any impact on whether you get invited for interview or not. But when it matters to a uni in shortlisting, then it really matters. And they might be looking for specific amounts or types of volunteering on either a PS or a different form that records it. So it really depends on who you apply to. But then that is the key thing with medicine. Be strategic and understand how the different med schools score your application. A lot of the strategic choices will be based on your UCAT so work hard to maximise that.
In terms of the work experience you have, although you will wish to refer to some in your PS, it’s really how you reflect on it and build on your learning at any interview that matters. Look at the RCGP reflection diary. Have a look at the BSMS online work experience.
Think about any public facing roles you have and when you have worked in a caring environment or have provided support in some way. If you don’t have that sort of experience, try seeking it out.
When you have your UCAT score go the Megathread for your strategic choices. Then it will give you a better idea of the relative importance of volunteering to your PS initial sift before interview. Good luck.