Should I re wire

[Midwest]

I wouldn’t bother looking at anything. Your a sparks, times your own. Wire it up, with what you want with the latest product, before you get too old

 

[pc1966]

As above, do a proper inspection & test before you decide what to do. At the very least you will need IR and low-ohms measurement like the old Megger, but it makes sense to borrow (or rent) a MFT for the job as that will also do Zs and RCD trip characteristics.

The 100mA incomer suggests it is a TT set up, or was when originally installed. Cables are going to be older than 2003 or so, but unless damaged PVC stuff will last many decades. So it might be you just go for a new CU with SPD and all-RCBO for the existing circuits.

However, wired smoke alarms and probably required, they can go off the lights so no new circuit necessary.

You probably will want more 13A sockets, but that might just be a bit of ring rejig to add more points.

In Scotland you don't have the Part P regulations (at least, not yet) but you absolutely must be able to properly test it. So that means getting access to test gear. I am sure you are quite aware of that, but I am commenting for anyone else reading this thread in a similar position! I have seen MFT for hire for under £100/week.

 

[pirate]

On the smoke/heat alarm side, in Scotland you will need to have these in place by February 2021. They do not need to be hard wired, can be 10 year sealed battery type, but must be interlinked, either wired or with wireless modules.