Upgrading old cavity wall insulation

My bungalow in Ireland has basic Jablite slab insulation in the cavities of 50 mm thickness. The walls are concrete block. I am not sure how effective or complete this may be. I have recently built a roofed conservatory with underfloor heating and 100mm floor insulation , double glazing and fibreglass roof insulation and it is noticeably warmer without any heating on.
Is there any product that can be injected into the original cavities to boost the UV value? Otherwise all i can do is double up on the loft insulation.All replaced wndows are now double glazed.

freddyuk said:

I have recently built a roofed conservatory with underfloor heating and 100mm floor insulation , double glazing and fibreglass roof insulation.

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surely this is classed as an extension?

noseall said:

freddyuk said:

I have recently built a roofed conservatory with underfloor heating and 100mm floor insulation , double glazing and fibreglass roof insulation.

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surely this is classed as an extension?

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Yes it is and it is built and insulated correctly. I dont understand your point?

a common understanding of the word 'conservatory' refers to a plastic or wood glazed building that has a glazed or plastic roof and does not or cannot comply with b'regs simply because of heat loss issues.

calling an extension a conservatory could lead to confusion.

the space in your 'extension' may be noticeably warmer because it is either heated more efficiently, is not subject to any thru' drafts or is as you say better equipped at retaining the heat.

if the cavities are already filled with inso' i don't see what else can be done in this location. doubling up in the loft sounds logical.