Sat Nav App aimed at caravan owners. This has been £49.99 for ages. You can input your caravan details and it will avoid suggesting routes unsuitable for your vehicle. Can download maps for use offline - so doesn't need a mobile data connection to work while travelling. Very useful if travelling outside the UK. Compared to hardware based Sat Nav units this price is an absolute bargain, and is the only app I've found to date which still works when offline.
Link is to IOS version - also available for Android https://play.google.com/store/apps/details?id=com.alk.copilot.market.premium.rv
Other Copilot Premium SatNav apps appear to also be included in the half price offer.