Help with cracks and gaps in brickwork surrounding windows

[puri]

We are looking to replace old aluminium windows with either PVC or Timber sash windows.

But the brickwork and timber around existing windows is eroding and there are large to fine gaps in brickwork.

The paint on concrete windows sills is chipping away.

I urgently filled large gaps last year with foam to stop leaks during heavy rainfall, but clearly didn't make good on it due to a temporary job.

However, I am now seeking advice on properly addressing these cracks and gaps around majority of our bedroom windows.

I don't feel this is something within the remit of window installers but keen on being advised otherwise.

When our neighbours had their windows replaced, the 'window people' simply put up a scaffolding and within few hours, had replaced all the windows and were done.

Newer PVC windows have exterior lining - perhaps I could specify wider lining to cover these gaps?

If the window installers cannot do this work, I could request they leave the scaffolding up for few days while either I or a local builder can carry out this work. The job at least to me feels time consuming and detailed hence the desire to incorporate some DIY.

I can reach the bedroom windows with my ladder but wouldn't know what to do once I am up there.

I've investigated using the following products:
Tetrion The Original All Purpose Ready Mixed Filler Tube, 330 ml
No Nonsence Mortar Repair Grey 310ML
Hybrid Polymers
Sika SikaFlex EBT+
Ready mixed mortar

The Victorian property does not have cavity walls so I find these gaps somewhat puzzling.

Thanks

 

[Wayners]

You need to talk to installers for options.

I know one local installer that replaces concrete sills with brick ones. You can also get them refurbished. Are you single skin brick walls?

 

[puri]

Yes single skin. Thanks.

 

[kp00110]

IM sure installers can use cover strips etc. Have you put a spirit level on the brickwork to see if it has bowed? The foam looks smaller and top and bottom and wider in middle - maybe brickwork has bowed out?

 

[puri]

You mean like this?

 

[puri]

Also, is anyone familiar with using mastic trowel to fill these types of gaps, and examples of some reputable products if there is benefit of using such a thing?
Thanks