Yeah, lanolin is a great and is used in many products. However, recently I read Fluid Film can cause swelling of natural rubber parts. However, Lanotec states their general purpose spray "cleans, rejuvenates and protects metals, timber, vinyl, plastic, leather, rubber, fibreglass and powder-coated surfaces". Lanox states "harmless to metal points & surfaces, plastics, painted & enamel finishes, fibreglass, formica or neoprene seals". The take should be that all lanolin liquids may not be the same and some could be a cause of concern when used with some materials. And since natural rubber is not the same as rubber, it could even be that Lanotec and MX4 Lanox could also cause natural rubber to swell. Sadly, there is no word on whether urethane would or would not be impacted by any of these sprays. Those that use it should probably ring up the spray manufacturer, explain their use of the product and ask for some guidance or assurance as to its suitability. As is, a one or two years period may not be enough to determine if the urethane bond on your windscreen has been negatively impacted. And if the bond strength is adversely impacted it may not be something that is visible until a rollover and the roof comes down.