Lots of collectors like low-numbered notes. Irish low numbers notes, especially of the Lavery series and Ploughmans are quite rare. I haven't seen many.
The hand-numbered terminator notes non-extended 100000 and 1000000 are even rarer!
Serial numbers were extended from 100000 per prefix to 1000000 per prefix on Lavery notes as below.
Prior to these dates prefixes changed at 100000 which was hand-set on the note.
Type 7. 10 Shillings from 12.9.51
Type 7. £1 notes from 11.9.51
Type 7. £5 notes from 6.8.52
Type 10. £10 notes from 9.2.60
Higher denominations did not have their serial numbers extended.National Bank Ploughman £10 note, number 000001:
More pics to follow...