Bush AC1 static on stations

[Hunts smoothing bomb]

Hi all,

I'm currently restoring the titled set, I have replaced all the wax caps and although it is working it is not receiving very clearly, every station is masked by heavy static interference, off station is quiet but as soon as you tune into a station the static is there, MW & LW also seem too quiet as SW is fairly loud but it is still masked by static.

I am using a long wire aerial about 15ft long that goes around the outside of my worksbop/shed, I have never had problems using this aerial with my other sets and it has always worked well.
I am wondering if I have a dud ECH3?, EF39 or EBC33 valve, I haven't tested the valves yet but will do hopefully tomorrow.

Has anybody else come across this problem before and know what causes it?
I was even begining to wonder if any one of the mica caps inside the I.F. cans could be duff?

Thanks in advance.

Cheers