Fire sprinkler systems for HMO’s – any thoughts?

We have a 3 storey Georgian terrace that we let as an 8 bed student property. All the ceilings are old lath an plaster, but in order to meet current standards, we should really board over every ceiling with plasterboard, incurring a massive cost, and also ruining much of the character of the rooms by removing the traditional cornicing.
We then have the issue of the old wallpapered walls which would be ruined at the top by removing the cornicing. Add to this the disruption to the tenants/loss of rent while the work is being done, decorating, cleaning up, the list goes on.

We can avoid all of this by putting in a sprinkler system, but how much will this cost? Does anyone have experience of installing a sprinkler system in an older property, would you recommend it? It would immediately solve all our issues, and even mean no more fire doors and auto closers.

It seems like a no brainer!

Regards

Jon Champion