The bearings you need are:
Upper: I/D 25mm x O/D 47mm x W 15mm (SKF 32005XQ)
Lower: I/D 30mm x O/D 55mm x W 17mm (SKF 32006XQ)
I use
simplybearings.co.uk for individual bearings, but the last headrace set (upper, lower and seal) I got came from
wemoto for �25 (USA made), which was just as cheap as getting the separate bits from a bearing supplier. They also do Koyo (which are the OE ones) for another tenner.
Just noticed you can get the whole kit from
Busters on ebay for �19.50 delivered, but I have no idea of brand or quality?