Unlike silver items, there is no date letter on silverplate allowing to recognize the date of its manufacture.
For silverplate items the patent's date of registered models may be useful for an approximate dating.
The 'lozenge' mark used between 1842 and 1883 to certify the patent of the models registered by the UK Patent Office allows the identification of day, month and year of their registration.
 

1842 - 1867	1868 - 1883
registry mark used between 1842 - 1867	registry mark used between 1868 - 1883

YEAR

LETTER

MONTH

LETTER

YEAR

LETTER

MONTH

LETTER

1842

X

January

C

1868

X

January

C

1843

H

February

G

1869

H

February

G

1844

C

March

W

1870

C

March

W

1845

A

April

H

1871

A

April

H

1846

I

May

E

1872

I

May

E

1847

F

June

M

1873

F

June

M

1848

U

July

I

1874

U

July

I

1849

S

August

R

1875

S

August

R

1850

V

September

D

1876

V

September

D

1851

P

October

B

1877

P

October

B

1852

D

November

K

1878

D

November

K

1853

Y

December

A

1879

Y

December

A

1854

J

1880

J

1855

E

1881

E

1856

L

1882

L

1857

K

1883

K

1858

B

1859

M

1860

Z

1861

R

1862

O

1863

G

1864

N

1866

Q

1867

T

This 'Bee case' patent is dated 27 June 1872: day 27 (upper corner) month June (lower corner M) year 1872 (right corner I)

From 1884 a numerical identification was attributed to new patent models. The table below reports the first serial numer attributed from 1884 to 1899