Product Page Layout

I am trying to change product detail pages to a one column layout using the code below:

@model ProductDetailsModel
@using Nop.Core.Domain.Seo;
@using Nop.Core.Infrastructure;
@using Nop.Web.Models.Catalog;
@{
    Layout = "~/Views/Shared/_ColumnsOne.cshtml";

in both ProductTemplate.SingleVariant.cshtml and ProductTemplate.VariantsInGrid.cshtml  and yet they still render as the two column layout.
What is overriding the layout?
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UPDATE

--  I've just switched the Nop Ajax Filters off and now the layout is responding, so now the question is:
is it possible to have the ajax filters on catalog pages, but have a one column layout for the product pages?

SOLVED

Took some time for the layout to catch up - Ajax filters and one column for product pages working fine!

Hi Jon,

Please note that the Ajax Filters work on the category pages only and they have nothing to do with the product pages. You can have whatever layout that you want on the product pages and this won't interfere with the Filters as the Filters won't show on any page different than a category page.

Thanks