OS 100km square number to letter conversion chart

Many of the individual records contained within the 
"Biological Records" provide the 100km grid square 
details as a two digit number (e.g. 61/456789) rather 
than the more modern two letter code (e.g. SD/123456). 
Below is a conversion chart.

00	SV
01	SQ
02	SL
03	SF
04	SA
05	NV
06	NQ
07	NL
08	NF
09	NA
10	SW
11	SR
12	SM
13	SG
14	SB
15	NW
16	NR
17	NM
18	NG
18	NB
20	SX
21	SS
22	SN
23	SH
24	SC
25	NX
26	NS
27	NN
28	NH
29	NC
30	SY
31	ST
32	SO
33	SJ
34	SD
35	NY
36	NT
37	NO
38	NJ
39	ND
40	SZ
41	SU
42	SP
43	SK
44	SE
45	NZ
46	NU
47	NP
48	NK
49	NE
50	TV
51	TQ
52	TL
53	TF
54	TA
55	OV
56	OQ
57	OL
58	OF
59	OA
60	TW
61	TR
62	TM
63	TG
64	TB
65	OW
66	OR
67	OM
68	OG
69	OB