There is but no access to diagrams.
Yep potential MOT fail on insecure battery!
Battery negative cover missing too but it may be down the side of the battery.
Basically there are 3 parts to it, the main top clamp and 2 stays as shown circled in red
There is also a nut for the front threaded bar and a clip at the rear of the battery box, part numbers are shown for each although the nut is generic ( M6 I think). Shown in blue.
74404A
CLAMP SUB-ASSY, BATTERY
74404-50030
1
€ 21.21
74407A
BOLT SUB-ASSY, BATTERY CLAMP
74407-50010
1
€ 5.71
74408A
BOLT SUB-ASSY, BATTERY CLAMP, NO.2
74408-50030
1
€ 6.25