Low loader and abnormal loads rates of pay

Been with my company for 8 months on bulk tippers and been offered the chance to move over to low loader work but they are trying to mess with the rates. This side of the company was bought over from another company and drivers that were employed with original company got transferred under tupe and are on a better rate ph than those on bulk tippers. Have been offered £10ph and £13.33ot rate but one of the original company drivers has said I should be asking for £12.25 minimum is this in the right ball park for this kind of work?

Does the company name begin with a P?
Deffo should be on more shifting machinery about,if it’s who I think get fair bit unsocial hours on rail jobs