Yesterday, Rutger sounded the alarm bell, and refused to carry on with the treatment until I had it checked out by my doctor. I've just come back from my consultation, and have been severely reprimanded. I am to 'take it easy' (and this time, she's taken care to explain to me exactly what I can and cannot do, so for one thing, I've been ordered to abandon my re-painting of the window frames and skirting boards for the time being - thank God I'd already finished most of it), and I'm not to even attempt to go back to the dreaded commute any time within the next 4 to 6 weeks.
Now all I need to do is inform Jobsworth, HR and the company doctor, and get them to agree to extend my sick leave for the duration. I have a feeling they're not going to be pleased about this, since the nature of my work means I can't do any of it from home.