My mother currently holds a tourist visa to the UK. She's now in Manchester with my step father. She wanted to know if it was possible for her to apply for the spouse visa while she is there or does she have to wait to get back to the Philippines (in July) before she can?
She’ll need to leave the UK to apply for a family visa if she has permission to be in the UK as a visitor. Applying to switch to a family visa as a visitor in the UK is only possible if you have either a 6-month family visa as a fiancé, fiancée or proposed civil partner, or permission to stay in the UK for the outcome of a family court case or divorce https://www.gov.uk/uk-family-visa
If she lives in the Philippines she has to go back there to apply for this category of visa (see paragraph 28 https://www.gov.uk/guidance/immigration-rules/immigration-rules-part-1-leave-to-enter-or-stay-in-the-uk) and to gather the required information https://www.gov.uk/uk-family-visa/provide-information