Grundfos UPS 15 45 x18 central heating pump?

The tests shown confirmed that my pump still works without the Capacitor .The Original Bosch Capacitor is rated as follows: 3uF ( microfarad) +/- 10% b
320V ~DB -25/85 degree C . It measures Length 60 mm x Diameter 25 mm .
I wonder which is the correct Maplin or other Capacitor to replace the original. The model shown in my local Maplin shop in Dublin was too large and I also was unsure about the rating. Any further advice would be appreciated.

Brian
December 2013