Can I help here Groundhog,
You can only do this with an outside the pole hose system.(generally ! )
Matts Diy site is down until the end of the month so heres one way of making it bigger.
Get a Ron Thompson Zensorflex from Swiftys fishing tackle £18.99 I use section 4 as a gooseneck for any modular tapered pole...... But Section 5 push fits inside the base section of the extended Harris.Wrap 8 rounds of pvc tape (blue in pic) round the top of the Glassfibre No5 to help make the pole fit snuggly inside the parallel alu base section. You have to remove the rubber grip using a screwdriver to slowly prise the glue away from the pole, its very hard work but you can then just push the grip back on when needed. I suggest you only add the modular sections when the pole is upright. Makes an actual pole of 8.5m plus your own reach of say 1-1.5m
If the pic doesnt load I will have to look at Lukes plan B for posting pics so give me time.
Also in pic is how to cut small sections of either a basic broom or an Unger No1 section. You can also slide a longer piece inside the Harris so that you can remove it at will for use on close downstairs work. Again just some rounds of tape until they wedge nicely inside.
