This is how I see it:
5.1.1 excludes damage to tyres ... except as a result of an accident which causes other damage
Hitting a pothole is an accident, therefore you should therefore be covered for your tyres as your rims/wheels and suspension were damaged as well.
The damage to your rims is not a concern of any of the exclusions, so you should be covered.
5.1.2 excludes damage to suspension caused by ... potholes
I haven't seen this exclusion in any other Motor Policy wording (and I work in the insurance industry). It is clear that your suspension damage is not covered under this exclusion, but you may wish your broker to argue that this exclusion defeats the purpose of insurance (to indemnify the insured for a fortuitous loss) and is not standard.
I wish you luck, and if you have no success with your insurer, get all your docs in order and claim from the municipality or department of public works. You'll need Pics of the pothole, Pics of the damage, three invoices, and possibly need to complete a claim form and a whole host of other documents.
The Short Term Insurance Ombud generally has sided with insurers where their policy wordings are clear and unambiguous, even if they are not the most fair, so I wouldn't advise this route.
Hollard probably has a "Pothole Extension" which they sell as an add on to their normal policy. They are also probably forcing you (rather than them as part of their subrogation rights) to claim from the municipality for admin sake.
Edit:
I spoke to a senior in our office, and he has said that 5.1.2 was probably to exclude gradual suspension damage over time as a result of continuous driving over uneven roads which may have potholes and they have just gradually changed it to apply to a single incident which should be covered. Not sure if this helps in any way.