And almost 3 years since doing my fix, some buzzing has now come back to haunt us once more. Not had a chance to catch the buzzing whilst it is happening yet, but I'll just replace all caps this time regardless...
The big axial capacitor is rated 63V 22uF, and the small radial capacitor is rated 16V 22uF. Maplin part numbers AT04 (43p) and VH09 (12p) respectively.
Old as the topic may be, I just want to thank DIYnot and in particular the above member for the advice. My delay timer relay went haywire this morning generating a most awful buzzing noise. Armed with Google and keywords I came across the above and today being Sunday the earliest opportunity...