Monarch Advance Brush??? Any good

Hi there,

I'm still having a lot of trouble with Painting window sills and architraves with Aquanamel (Acrylic) High gloss paint.

It seems to show the brush marks as isn't hugely glossy.

I have dded some floetrol to some and it seems better.

The brush I am using is a Bunnings. Monarch Advance - 38mm Rat Tail Sash Cut. It was only $4.70.

Is this the weak link. THe brush seems quite nice but wondering if it is the main reason for the brush marks. It is made by an australian company.

should I spend up more and get a better one? I asked the guy there and told him I didn't want to skrimp on the brush due to the importance of it but he said that the $4.80 ones were good!

Shoudl I sand between coats?

Thanks

Any ideas apprectiated and most importantly your vies on the brush