Hate to sound defeatist on this but I'm not sure what material planning grounds there are going to be to refuse this application. The parade is fairly small but still has a number of eat-in/A3 class units so there isn't pressure to retain that unit at its current use. I'd guess it'd be difficult to find a technicality on which the PA could be refused too (given that Dominoes are a large company and will have specialists working on their planned units).

I'd have thought your best bet would be to garner a lot of local support to encourage Dominoes to apply more sympathetic branding than they usually would, based on your assertions about the quality of the building. However, it isn't listed or (I believe) in a Conservation Area so there wouldn't be any obligation from either Dominoes or LBL to support this.