The ILS at Sheffield was pulled because it was a white elephant at an already closed airport.
To maintain an ILS, even to CAT I, you need engineers to check it every months (field pattern check and monitor checks every three months) and for it to be flight checked by a CAA approved organisation every 6 months (Around 10k per visit!).
I think the Sheffield ILS went to Doncaster Sheffield Airport for their other end, I'm not sure, or Doncaster may have put CAT III on one end and moved their existing CAT I to the other end.
Sheffield airport was a basket case but that's another argument.
