The United Kingdom with its robust economy and official English language became a magnet for Lithuanian migrants after 2004 when Lithuania joined the European Union. Some 100 000 Lithuanians left their homeland for the UK - more than ever to any single country except for the pre-WW1 migration to the USA.
However, unlike the Lithuanian-Americans, the Lithuanians of the UK are not building massive Lithuanian schools and churches - for now at least. However, there is Lithuanian heritage in the UK: it has been created by much smaller groups of 1880s-1950s emigrants who chose what was then British Empire over the USA for their new lives (such a migration was cheaper). Back in Lithuania (then ruled by the Russian Empire) ethnic Lithuanians faced discrimination, had their language banned, lacked any industrial jobs, while males could have been conscripted for many years.
Exact figures of Lithuanians are hard to get as the British census asks for broad racial categories rather than ethnicities (Lithuanians are among "Other Whites").
Lithuanian heritage in London and its suburbs
Most of the UK Lithuanians live in the capital London (40 000 - 80 000) where they make up ~0,5% of the population. There is no Lithuanian neighborhood there, however, although the traditionally poor East London has somewhat larger Lithuanian populations. The Lithuanian St. Casimir church is also located there, having been constructed by pre-WW1 immigrants in 1912. New Lithuanian migration saved it as a viable parish. London also has a historical Lithuanian cemetery where (among others) some famous interwar Lithuanian diplomats are buried (Soviets did not permit them back home). Today however Lithuanians are buried in all cemeteries.
The Lithuanian parish of London owns a farmstead-hotel in Headley Park suburb since 1955 (Guildford GU35 8TE). Lithuanian holidays are held here, with Pentecost being the most important.
Lithuanian heritage in Scotland
Prior to the World War 1 some 8 000 Lithuanians lived in Scotland. Most of the adult males worked in the coal mines of North Lanarkshire near Glasgow. The Mossend district of Bellshill town there still has a Lithuanian Social Club (79A Calder Road). Since 1904 the nearby Holy Family church has Lithuanian mass. Lithuanian priests (especially Gutauskas) who once made this possible have a cross and a monument dedicated to them. Pre-WW1 Lithuanians sought to build their own church like their brethren in the USA were doing. However, the UK of the era was far less tolerant and the local bishop prevented establishing ethnic churches. Bothwell cemetery still has Lithuanian graves that look very British: with long descriptions of birth and death dates, additional information. The areas top pilgrimage site, the Carfin grotto, has a Lithuanian inscription in addition to other languages.
Unfortunately, the pre-WW1 Lithuanian community in Scotland had a rather terrible fate. There was still no independent Lithuania therefore, as BBC notes, Lithuanians were "Russians" to the government and "Poles" to most Scots. The founder of Labour Party Keir Hardie denounced the import of these "Poles from Russia" (i.e. Lithuanians). In 1917 Britain signed a deal with Russia forcing the Scotland's Lithuanian males to serve the Russian army. ~1200 have been sent away, some found Russian Empire already collapsed, but few were able or wanted to return to Scotland. As Lithuania gained its independence in 1918 some established their lives there, others perished. The diminished Lithuanian community in Scotland has been somewhat rejuvenated ~1950 by refugees from Soviet-occupied Lithuania. Like elsewhere in the UK post-2004 migrants now form the majority of Lithuanians in Scotland.
Among the pre-WW1 Lithuanians in Scotland was the infamous communist Vincas Mickevičius Kapsukas. Having failed to promote communism in Lithuania ~1918 he was accepted into the "Soviet pantheon" after the Soviet Union occupied Lithuania (1940) and even had a town named after him there in 1955 (which the local people voted to rename back to Marijampolė immediately after the democracy returned ~1989).
Lithuania-related places elsewhere in Britain
Other British locations never had Lithuanian communities large enough to leave massive heritage. The actions of modern Lithuanian emigrants are not yet visible in stone. Such a massive community made it possible to establish commercially viable Lithuanian Sunday schools, a small shop chain "Lituanica". However "Lituanica" stores also have Polish and Russian adverts and sell various Eastern European goods. When there are no Lithuanian neighborhoods with a concentrated Lithuanian market such multi-ethnic orientation is a necessity for a profitable business. Lithuanian shops, stores, bars, and schools are all operating in rented premises, Lithuanian mass is held in non-Lithuanian churches. Should this continue it is likely that after the Lituanity will start its inevitable decline (Lithuanian kids born in Britain are already assimilating) and the institutions will start closing down this massive community will leave little heritage.
British laws aren't especially convenient for Lithuanians. Lithuanian is not allowed as a medium-of-instruction at schools (except for special Sunday schools). Discrimination of Lithuanians and other Eastern Europeans isn't regarded as seriously as discrimination of, for example, Black immigrants. There is also less government support for Eastern European minorities culture.