Ignore that link, no stock. Will try variable attenuator first then look at new amplifier, that one you mention is £11 on Amazon.
It does not have a 4G filter, and you do not need a digital bypass, as that is for Sky satellite systems.
The Amazon one should be fine, but you may still need the attenuator if the output level is too much.
As you have said, try the attenuator first.
Any good SLx 8-Way Distribution Amplifier
That should be fine, as it includes a 4G filter, its the same make as the Amazon one but it has rather a lot of signal gain, and far more outputs than you need. Try the attenuator first.
PS, Its best not to post direct links to e-commerce sites, just the description of the item, and where it come from.
The connector is always useful to have for fault finding, as you can temporarily bypass the amplifier, just in case that is making matters worse.
Plenty of things to try over the weekend
Will go for the Amazon one you suggested if needed.
It would bring your system up-to-date, as you no longer need VHF features, that was a very long time ago.