Are services of QS/Project Manager accessible only with an architect’s plan/involvement?

Is it possible to engage a QS/PM to work out a budget costing and supervise a simple renovation without architectural plans, or is this service only available with an architectural plan or architect involved? My project is not a new build or an extension. Really more cosmetic in nature, ie crack repairs, insulation, replacing sanitary ware, stripping and replacing a kitchen, replacing floor coverings, building a boundary wall/fence, etc. Most of the quotes I’m getting are (IMO) extremely high for what’s involved. I also have no way of gauging the cost of materials vs labour as Tradespeople/Construction companies are reluctant to supply detailed quotes, so it's difficult to know what the cost of materials is vs the cost of their labour. I’m also concerned at the lack of transparency in supplying specs for the materials. I’d like to believe I’m getting what I pay for, but when there is no transparency, I feel I’m left out on a limb; I’m retired and don’t have a bottomless pit of cash to throw around, or the confidence to take chances on being preyed upon by an unscrupulous or bogus tradesman/construction companies. Judging by the horror stories one reads/hears about, I feel it can happen to anyone. I don't want to be that person. If anyone managed to engage a PM or QS to manage their project, please, please, please tell me how you went about it. Thanks.