Phone up your local electrical wholesaler and ask them if they can supply replacement screws for that type of Crabtree CU should only be a few pounds at most.  Alternatively go on ebay and buy the same CU for £10 to £50 just for the screws which hold the front cover on.

Longer term you will need to consider a new Consumer unit with RCBO and SPD in a metal enclosure but for now the EICR should be done to the edition on the CU/board when it was fitted.

Thanks for the help. Wanted to check do you agree this would be C2? 

> consider a new Consumer unit with RCBO and SPD in a metal enclosure
Yes, I do agree this is a long term solution. The place do need some renovation, but not now.

>the EICR should be done to the edition on the CU/board when it was fitted.
This makes sense.

Do these screw looks right? I haven't opened an CU before and don't intend to.
Just to check they are suppose to look that long.

www.ebay.co.uk/.../281879121282

I say say no.  Those screws look like what you would use on the front of a socket or light switch

They probably gave it a C2 due to IP rating (international Protection) mistakingly called Ingress Protection by many.  Either way it's a situation that you could get a finger in there or a 1mm CSA cable.  There are different IP ratings for the top of the CU and the front.

I think it is

horizontal is IP4X (ie 1mm) and vertical is IP2X (ie finger size)

From memory the metal crabtree units used M5 screws or M4 on the older ones. Plastic were a coarse self tapper. Take the one you have out to check the length and walk it over to your local screwfix/toolstation whatever and buy a bag of anything that matches.  I don't think anyone will care if its mild steel, nickel plated brass or marine stainless. However a woodscrew at a jaunty angle would alarm.

I presume that when only half supported, the cover flaps about and you could bend it away from the box and touch something live behind it. If not C2 is a bit steep, and  'replace whole CU' assuming the rest of the issues listed are honestly all that is wrong, is borderline fraudulent.

Regulation 134.1.1: Good workmanship by one or more skilled or instructed persons and proper materials shall be used for the erection of the electrical installation. The installation of electrical equipment shall take account of manufacturer’s instructions.

does rather imply if there are N screw holes, more than N-1 screws should be fitted - but replace the box !?

The only 'gotcha' would be if the thread it is supposed to engage with has been stripped out. Even then there are 20 minute solutions known to those skilled in the arts.
Mike

From memory the metal crabtree units used M5 screws or M4 on the older ones. Plastic were a coarse self tapper. Take the one you have out to check the length and walk it over to your local screwfix/toolstation whatever and buy a bag of anything that matches.  I don't think anyone will care if its mild steel, nickel plated brass or marine stainless. However a woodscrew at a jaunty angle would alarm.

I presume that when only half supported, the cover flaps about and you could bend it away from the box and touch something live behind it. If not C2 is a bit steep, and  'replace whole CU' assuming the rest of the issues listed are honestly all that is wrong, is borderline fraudulent.

Regulation 134.1.1: Good workmanship by one or more skilled or instructed persons and proper materials shall be used for the erection of the electrical installation. The installation of electrical equipment shall take account of manufacturer’s instructions.

does rather imply if there are N screw holes, more than N-1 screws should be fitted - but replace the box !?

The only 'gotcha' would be if the thread it is supposed to engage with has been stripped out. Even then there are 20 minute solutions known to those skilled in the arts.
Mike

> rather imply if there are N screw holes, more than N-1 screws should be fitted

Thanks for the quote on 134.1.1. I can see where the interpretation comming from.

>The only 'gotcha' would be if the thread it is supposed to engage with has been stripped out. Even then there are 20 minute solutions known to those skilled in the arts.
I do have the same thought. The missing of the other screw and the incorrect screw do imply someone had stripped the thread. Could you share more detail on how to fix the screw if it's indeed stripped?

Would go up by a size count work / aginst the regulation? 

Depends what has happened inside. The best thing is to carefully remove the cover and take a few pics. Unless you are very  confident, that should be best done with the power off just in case there is a live end in finger grabbing distance as you curl your fingers around the edge to remove it.

Mike.

PS if you are not too confident about that, at least have someone with you watching where you put your fingers. Those of us who push electrons about for a living get quite careless about undoing covers with the power on, when we know what to expect behind - but you probably should not copy that without having seen inside one already and knowing where there wont be anything.