I have a balustrade which needs sorting see below. Basically it was put together with ordinary mortar and some of the uprights are loose so I have taken part of it down to re-cement it. I would appreciate some suggestions on what to use to cement it all back together again ie do I need some special additive to ordinary mortar or should I be using something different like a grout mix. Any suggestions welcome. Thanks

 3 x FL1 2 manual + 1 auto
5 x FL2 4 manual + 1 auto
Now Discovery Sport P250 MHEV SE

I would use a strong mix with a good dollop of PVA glue if it were me.

Builders today often seem to use stuff out of a squirty can to lock in walls etc. Tell someone to bring in the washing though.  FL2 MY10 TD4 GS traded in at 2 years
FL2 MY13 TD4 GS Current

Some info here.
http://www.kentbalusters.co.uk/popups/bodiam-fixing.html Past: FL2 TD4 HSE Auto
Evoque SD4 Dynamic Lux Auto
Present: Audi A3 S Line.