Oh come on guys!
Its just a couple of typos and grammar mistakes!
Instead of lingering on these errors, why not actually ANSWER the question the OP asked and be useful?
To OP - Your work ex seems fine, but make sure you've done one of them as a long term thing, like your work at Cancer Support UK.. also, see if you can get involved and help out at a local hospice or an old peoples' home; and like someone mentioned earlier, the most important thing, instead the actual work ex itself, is how you reflect on what you have done, and what you've learnt from the experiences - and make sure you put emphasis on this in your PS.