Top 30 recommendations for SHTF security in the average brick house:

Spread preps around friends and families homes.
Build a mutual assistance group.
Build a surveillance network of neighbours, drones or cameras, etc.
Hide your preps and use of them.
Live where neighbours can see you but not strangers, and not too isolated or crime riddled, and avoid flats.
With small gardens and being open to the street, fences are of little use, but if you want a fence, add a topper and cover it with an alarm (driveway alarms), cameras (eg camo cams, UWatch Cube) and (eg PIR) lights.
Reinforce gates with plywood and/or exmesh.
Trim vegetation. Plant hawthorn under windows and roses up fences.
Hide tools. Lock up and lock down your gear.
Upgrade sheds with a beefup kit, and ideally replace with a metal shed.
Store a fortification kit for SHTF.
Deploy anti climb products.
Avoid key safes.
Cover meters with lockable overboxes.
Wall penetration need grilles of 0.5” steel bars at 6” centres each way. Replace extractor fans with a polycarbonate security version.
Lock your car with extra devices, ideally in a garage.
Plan an escape route.
Build concrete planters if ramming is a risk.
Rig up battery/solar powered cameras, alarm and lights. Mains powered systems will not last long after SHTF, so fit British standard lighting, alarm and CCTV for use until then, just do not rely on it once electricity, phones and internet goes down.
Consider a guard dog.
Consider lining unreinforced masonry with 18mm plywood, 3mm steel or 3.7mm exmesh, and if only 4” of brick consider sandwiching exmesh between plywood.
If the hardened facade worries you that intruders will come through the roof, spread the weight of reinforcement by lining the roof, loft and ceiling with 8-15mm plywood and exmesh or Securilath, replace the loft hatch with a locking version and consider steel roof tiles.
Replace glazing with 0.5-1.25” polycarbonate, ideally at least 22mm (eg ESG Secure 22.5mm, Hamilton Erskine Tecdur 20mm), and replace as a framed unit for strength and locking (eg Crittal Fendor Secureline, Hampton Quattroglide, Sash Window Conservation Sash Secure 240 Embassy, Selectaglaze SR2, RappBamek Stalprofil RC5, Salzer aluminium RC5), or add SR2/SR3 grilles (eg RSG14000, Extendor C42/Eclipse, Securablind Defender, Trellidor T3000), or SR2/3 roller shutters (Hart Terror Screen, Harlech Crimeguard, Clark Multigard, Charter Obexion, CGT Xonar, Ascot 320/Centurion, Rolux SOL, Aluroll I100 Elite). Keep something like black landscape fabric ready for blackout.
Replace doors with SR2/SR3/RC5/RC6 steel security doors such as Assa Ultimum, Bradbury M2M, Stafford Bridge Sandhurst, Securdoor. Only one should be your exit door with an external keyway.
Treat an in-use garage door as a window in terms of adding a security roller shutter, as there is not much of a market for swinging security garage doors, otherwise screw it shut and board it up from behind.
Consider an active delay system such as FogBandit.
Consider building a saferoom, typically using grouted reinforced hollow concrete blocks and/or plywood and exmesh. You can also buy modular panels or liners such as fibreglass, Avertix, Burton Talos, Securilath, Isoclad Securiclad, Remtech Modusec, R&D Sheet Metal Evo.
Stash self defence products about the home, like a baseball bat, cricket bat, fibreglass umbrella or walking stick and dazzle torch.
Learn a grappling martial art like BJJ and something for high speed destruction like Krav Maga.
Join a shooting club and get yourself a shotgun with some 00 buck.