The total investment during 2017=£4,500,000.
The present value of the expected returns at 12% per annum starting at 2019 is
2019 £300000/1.12²=£239158.16
2020 £400000/1.12³=£284712.10
2021 £500000/1.12⁴=£317759.04
2022 £600000/1.12⁵=£340456.11
2023 £700000/1.12⁶=£354641.78
2024 £800000/1.12⁷=£361879.37
2025 £900000/1.12⁸=£363494.91
2026 £1000000/1.12⁹=£360610.03
2027 £1100000/1.12¹⁰=£354170.56
2028 £1200000/1.12¹¹=£344971.32
2029 £1300000/1.12¹²=£333677.62
2030 £1400000/1.12¹³=£320843.87
2031 £1500000/1.12¹⁴=£306929.72
2032 £1600000/1.12¹⁵=£292314.02
TOTAL Benefits=£4575618.61. Net Present Value=£4575618.61-£45000000=£75,618.61.
However, since the second investment was made 9 months after 1 January, 2017, it could be argued that the present value of the second investment in January was 2000000/1.09 (¾ of 12%) =£1,834,862.39 making the total investment on 1 January 2017, £4,334,862.39 instead of £4,500,000. This would change the NPV to £240,756.22.