There are commercial beekeepers who sell pollination services in the UK. However, there are a number of issues which you might wish to consider related to this topic.
1. In the past, and in the most natural environments, there was/ is no need to buy in pollination services because the natural environment supports a healthy population of wild pollinators (not just the honey bee) and pollination is achieved freely, unnoticed by most of us. Pollination services are required when we have created an environment which no longer supports a large, healthy population of wild pollinators. A typical example is single-crop monoculture. It is the vastness of monocultures and the eradication of natural environments in California, which has given rise to the largest honey bee pollination businesses in the world. In China the inability of wild pollinators or beekeepers to meet the ever growing and highly intensive pollination demands has meant that apple pollination is sometimes done by hand. Hobby beekeepers living and working in mixed landscapes have always -indirectly- provided pollination services for others, but they cannot easily meet the needs of intensive agriculture in mono-crop landscapes. Apple growers in the UK used to keep their own colonies within their orchards for pollination, but now find it cost-effective to contract out pollination to beekeepers who truck the bees in and out of the orchards. Some prefer it because they can then spray the crops with pesticides when the bees are not there - if they kept their own bees permanently, they would not be able to do this. In other words any environment which needs to employ the services of a commercial beekeeper for pollination may be a damaged environment.
2. Mobile beekeepers. Beekeepers practicing commercial pollination move their bees around from orchard to orchard and crop to crop. This necessitates mobile beekeeping which we believe is unnatural and unhealthy for the bees. The risk of spreading diseases is increased, but even more importantly, the bees can be stressed and therefore will succumb to viruses where healthy bees can resist these problems. Mobile beekeeping is therefore not \"ecological\" and is unsustainable. In the USA there are huge mobile beekeeping operations - it is normal for beekeepers to keep buying new queens year after year, unwilling or unable to keep their colonies healthy and self-regenerating.
3. Bumblebees. Bumblebees are valuable pollinators for some poly-tunnel crops - partly because they are better pollinators of those crops (e.g. tomatoes) and partly because honey bees do not do well in tunnels and greenhouses. Commercial bumblebee pollination is achieved by growers importing bumblebees from the Netherlands (for example), using them for a season, and re-importing again the following year. This is not only unsustainable but the imported bumblebees can bring diseases and affect our indigenous bees in terms of genetic fitness.
The truly sustainable and environmentally good approach to pollination is the creation of landscapes and environments which can support and maintain our indigenous pollinators. As a result of the Varroa mite honey bees (Apis mellifera) no longer live wild in the UK therefore beekeepers play an important role in maintaining their populations - however it is important for beekeepers to consider the natural behaviour and health of the honey bee and prioritise bee welfare. Intensive, mobile beekeeping is probably inconsistent with this.