I own a flat above a lighting shop that I am trying to sell. The buyers' solicitors have asked for a Fire Risk Assessment which I don't have and the Freeholder hasn't arranged. 

The building: a double fronted building organised as a semi detached, with two flats above each commercial unit (one is a lighting shop and the other is an Indian takeaway). Our side of the building (and the other I believe) has separate access to the flats. The conversions into flats were completed in 2006. 

Am I right in thinking that as the renovations were done in 2006 (and assuming they were done correctly), there is no need to link a fire alarm system between the commercial and the flats? and so similarly, there is no need to have a communal detection system? 

Yes, if the compartmentation is adequate (60 mins) between the shops & flats. The commercial units FRAs should have already looked into this as the flat occupiers are relevant persons under the legislation, however many are non existent or poor so may have overlooked this.

As there are no internal common areas the Freeholder has no doubt assumed they have no requirement to do an FRA and as they don't have control over the premises they didn't used to, but as the building has two or more dwellings they may be required to assess the external wall construction.