I'm in the process of getting my parents set up for the digital switchover, and would appreciate some advice on the best way to wire up the wall plates for their installation.

Their house was built in the early 1980s and has had existing tv aerial wiring in the walls to an external point on the roof which has never had an aerial fitted. The TVs in the house actually got fairly acceptable Freeview reception just off the wiring in the walls, but had trouble picking up TV3 and other channels on the same frequency, so I arranged to get a UHF aerial installed and attached to the existing wiring.

The installer had some reservations about using the existing wiring because it was so old, but running a new cable (either internal or external) isn't really a practical option. Unfortunately it looks like he was right, and hooking up the aerial didn't actually improve the signal at all (vs hooking up to the in-wall wiring with no aerial). After trying a couple of things, the installer decided there wasn't anything he could do for us short of replacing all the wiring, and left.

I decided I would have a go at replacing the aerial jacks in the house, and see if that made any difference. The aerial is wired into the lounge jack, which then has another cable twisted into the jack daisy chaining it to the jack in the dining room (i.e. there is no splitter installed) - see below.

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aerial        lounge            dining

I replaced the dining room jack with a new Belling Lee connector (the wire is similar to RG6 but thinner, and with a braided central core meaning I can't wire f-connectors), which gave me strong reception in the dining room. I also opened up the jack in the lounge where the wires are twisted together and gave that join a bit of a clean, which now gives much better (but not perfect) reception in the lounge. 

The setup now allows for use of either jack, but not both at the same time, which makes me think I need to insert an amplifier somewhere in the chain. I'm thinking that I will rewire the lounge jack to separate out the wires (see below) which means I can then patch in an external amplifier splitter like this one http://www.kingray.net.au/products/splitter-amplifiers/indooroutdoor/SA162F.

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aerial        lounge            dining

The guy at the electrical wholesaler turned his nose up at this and said I should be installing a splitter into the ceiling space, which unfortunately isn't really an option given these appear to use f-connectors, and there is no access to the cable other than at the jack points.

Would appreciate any views on the best approach here.