In 2017, the relative value of £125 from 1880 ranges from £11,830.00 to £205,600.00.

This may not be the best answer.

The best measure of the relative value over time depends on if you are interested in comparing the cost or value of a Commodity, Income or Wealth , or a Project.

If you want to compare the value of a £125 0s 0d Commodity in 1880 there are four choices. In 2017 the relative:
real price of that commodity is £11,830.00
labour value of that commodity is £58,730.00
income value of that commodity is £95,660.00
economic share of that commodity is £205,600.00

If you want to compare the value of a £125 0s 0d Income or Wealth , in 1880 there are four choices. In 2017 the relative:
real wage or real wealth value of that income or wealth is £11,830.00
labour earnings of that income or wealth is £58,730.00
relative income value of that income or wealth is £95,660.00
relative output value of that income or wealth is £205,600.00

If you want to compare the value of a £125 0s 0d Project in 1880 there are three choices. In 2017 the relative:
real cost of that project is £13,130.00
labour cost of that project is £58,730.00
economic cost of that project is £205,600.00

To read the earlier E-Sylum article, see:
MORE ON READY'S BRITISH MUSEUM REPLICAS (https://www.coinbooks.org/v21/esylum_v21n12a10.html)