What is the position of the UK Methodists on pre-marital sex?

The documentation from the 2021 UK Methodist Conference does not appear to say anything about couples who are sexually active outside of marriage other than to say a range of views were expressed on cohabitation and same sex marriages.

Here are a few extracts from the official source: https://www.methodist.org.uk/about-us/news/latest-news/all-news/conference-confirms-resolutions-on-marriage-and-relationships/

Following prayerful consideration by the whole Church, the Methodist Conference has voted to confirm provisional resolutions on the principles or qualities of good relating, understanding of cohabitation and same sex marriages conducted on Methodist premises or by Methodist office-holders.

A report on marriage and relationships, ‘God in Love Unites Us’, was received by the Conference in 2019 and the local District Synods were asked to consider the provisional resolutions and report back to this year’s Conference which is being held this week in Birmingham. The Conference received a report on the results of the local conferring which showed that 29 out of the 30 Synods confirmed support for the provisional resolutions.

A range of views were expressed on the resolutions, in particular on cohabitation and same sex marriages. The Revd Dr Jonathan Hustler, spoke to the Conference acknowledging the “depth of feeling, pain and anxiety that there is” with a commitment to work across the Connexion with District Chairs to heal divisions.

Speakers called for unity going ahead irrespective of the decision. Other speakers spoke of the acceptance of diversity that younger Church members have for each other with younger speakers relating their own lived experience as Christians from the LGBTQI+ community. Another representative asked that the Church does not ostracise those who oppose the introduction of same-sex marriages in the Church, saying the great majority of these people are trying to be faithful to Scripture as they see it.

The Conference confirms resolution 10/8 of the Conference of 2019, as originally adopted:

The Conference consents in principle to the marriage of same-sex couples on Methodist premises throughout the Connexion and by Methodist ministers, probationers or members in so far as the law of the relevant jurisdiction permits or requires and subject to compliance with such further requirements, if any, as that law imposes. https://www.methodist.org.uk/media/21969/conf-2021-59-marriage-and-relationships-provisional-resolutions-updated.pdf#page=26

Frequently Asked Questions following the 2021 Conference votes on Marriage and Relationships were to do with practical and legal aspects concerning the registration of Methodist churches to enable them to comply with the law.
Individual churches are under no obligation to conduct same sex marriages. For example:

Our Church Council does not want to register its building for same-sex marriage. Does it have to? No. The Conference recognises the differing views across the Connexion on the issue of same-sex marriage. The fact that the Conference has consented in principle to the marriage of same-sex couples on Methodist premises does not change this, and it is vital that local churches understand that they are under no obligation to register. They are entitled to decide against doing so if they wish, or to decline to consider the issue altogether.

Can we register our Methodist church building if we share it with another denomination under a Sharing Agreement? It should be noted that any denomination who is a party to a Sharing Agreement under the Shared Building Act 1969 has the power to veto a registration of the building for same-sex marriage.

I am the authorised person for conducting marriages in my local church. I do not wish to solemnise same-sex marriages. Can I be compelled to do so? No. The Marriage (Same Sex Couples) Act 2013 amended the Equality Act 2010 to state that people will not be breaking the law if they refuse to conduct, participate in or attend a same-sex marriage.

The issue, it seems, has to do with facilitating the marriage of same sex couples in the Methodist church. No mention was made of either endorsing or celebrating couples who are sexually active outside of marriage.