Most varieties are self fertile, plants will always fruit better and produce heavier, more regular crops if pollinated by another tree - either the same or a different variety.

Double grafts are available and these have been specially designed for their ability to pollinate each other, hence you only require one tree.

Cultivar|Pollinator

Aprigold Dwarf|Self fertile

Castlebright|Self fertile but best with more than one tree.

Cluthagold|Sundrop, Moorpark

Cluthalate|Self fertile

Earliril|Sundrop

Fitzroy|Self fertile

Garden Annie Dwarf|Self fertile

Goldbar|Self fertile - Good companion/pollinator for most other varieties

Goldrich|Earliril

Goldstrike|Goldbar

Katy Cot|Self fertile

Moorpark|Self fertile

Newcastle|Sundrop, Goldbar

Royal Rosa|Self fertile

Sundrop|Trevatt, Goldbar.  Good companion/pollinator for most other varieties

Tomcot|Self fertile 

Trevatt|Self fertile 

Trevatt|Self fertile

Trigems|Self fertile