Personally I would go for all RCBO with an older property so if there are issues with a circuit, only that circuit is affected. As to make it would depend on the supply type, there are single slot duel pole RCBO's that can be used with TT supplies, but only with the more expensive makes. The problem with more expensive makes is the SPD also becomes more expensive, so total cost really goes up. Fusebox and British General (BG) seem to make reasonable boxes if you don't need twin pole switching.
The other problem is getting type A RCBO's, I know Fusebox and BG do a type A, but
Screwfix does not it seems stock the type A, CEF lists a type A at £23.94 but type AC in
Screwfix down to £11.99. The same with FuseBox the type AC rather cheap, but type A more expensive.
I made a mistake with my own house, I saw type B written on the box and thought Oh good did not expect type B but in fact it was curve B type AC and did not realise until after the electrician had fitted them all.
So if you want type A there is not so much of a saving using the cheaper boxes, as to if we really need type A not so sure, I ordered up type A for my ring finals, but due to Colvid I suspect they never arrived at retailers so cancelled. And I am using all type AC. If I go for an EV will have no option but change to type A, but not convinced really required.
If not going down the RCBO route, then be aware all RCD's are not equal. The spec says between 15 and 30 mA they must trip and at 5 times trip in 40 mS, but some makes don't say 50% to 100% but 90% to 100% like the X-Pole and also have a warning when approaching the trip point. We should test first, I have a insulation tester so no problem testing the insulation, but that is DC, what we really want is the actual leakage current, so a clamp on ammeter with a 0.001 increment scale, multi circuits should not exceed 9 mA in the main the loop impedance meter uses around 6 mA with no trip test, but it was enough that in my old house I could not use the loop impedance meter on one RCD, yet the 50% no trip with RCD tester passed.
What you want is for the RCD to protect but not nuisance trip, and to be sure really need to test existing installation first, that's why I went all RCBO in last house I would get a bout of trips with no fault found, then years with no trip. Fitted in around 1992 I would say lost around 3 freezers full of food, so feel safer with RCBO's. No longer permitted auto reset types in domestic.
So you in some ways you get what you pay for, in theory a consumer unit is a type tested distribution unit and to keep the type testing you can only fit devices recommended by the manufacturer, so can't fit a BG RCBO in a Wylex consumer unit even if they will physically fit. I have seen it done many times, and with an EICR only code C1, C2, and FI is a fail, and it would be hard to say wrong make is potentially dangerous.
I fitted an external isolator and had to extend cables for some circuits, and fitted a fusebox make which cost around £250 for materials but included wire, crimp pliers, and other bits, and I have 14 RCBO's fitted. When I got a leak I was glad I could simply switch off some sections without effecting others, had I used MCB's I would have had to drop tails to stop neutral to earth faults.
I am not saying what to do, just giving food for thought.
