Don't know how to locate the trailer fusebox 2012 L322 RR Westminster

The L322 does not have a trailer dedicated fuse box.
Trailer fuses are follows:

Glovebox fusebox :

#11 - Trailer reverse lamp
#27 - Trailer side lamps
#48 - Trailer connector (battery feed)

There is further fuse #8, listed simply as "Trailer".
This is to be found in the fusebox behind the rear loadspace access hatch on the right hand side.

See Owners Handbook, p234.

Warwick 2011 L322 TDV8 A/b Orkney Grey
2008 Defender 90 XS TDCi Java Black
2002 L322 TD6 Vogue Zambezi Silver (gone but not forgotten)
And one or two bikes - Ok, maybe more than one or two....